diff --git a/action.go b/action.go
index 9dc0940..39ff2aa 100644
--- a/action.go
+++ b/action.go
@@ -50,21 +50,24 @@ type ActionDataCard struct {
 }
 
 // GetActions make a GET call for a board's actions
-func (b *Board) GetActions(args Arguments) (actions ActionCollection, err error) {
+func (b *Board) GetActions(extraArgs ...Arguments) (actions ActionCollection, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/actions", b.ID)
 	err = b.client.Get(path, args, &actions)
 	return
 }
 
 // GetActions makes a GET call for a list's actions
-func (l *List) GetActions(args Arguments) (actions ActionCollection, err error) {
+func (l *List) GetActions(extraArgs ...Arguments) (actions ActionCollection, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("lists/%s/actions", l.ID)
 	err = l.client.Get(path, args, &actions)
 	return
 }
 
 // GetActions makes a GET for a card's actions
-func (c *Card) GetActions(args Arguments) (actions ActionCollection, err error) {
+func (c *Card) GetActions(extraArgs ...Arguments) (actions ActionCollection, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("cards/%s/actions", c.ID)
 	err = c.client.Get(path, args, &actions)
 	return
diff --git a/arguments.go b/arguments.go
index 5830759..02b7d3c 100644
--- a/arguments.go
+++ b/arguments.go
@@ -25,3 +25,21 @@ func (args Arguments) ToURLValues() url.Values {
 	}
 	return v
 }
+
+// flattenArguments will return a Arguments by merging a slice of Arguments,
+// where each successive slice can override fields in the previous.
+func flattenArguments(extraArgs []Arguments) (args Arguments) {
+	args = make(Arguments)
+	args.flatten(extraArgs)
+	return
+}
+
+// flatten will merge a slice of Arguments into the current one
+// where each successive slice can override fields in the previous.
+func (args Arguments) flatten(extraArgs []Arguments) {
+	for _, extraArg := range extraArgs {
+		for key, val := range extraArg {
+			args[key] = val
+		}
+	}
+}
diff --git a/board.go b/board.go
index a357d50..0e0a2d6 100644
--- a/board.go
+++ b/board.go
@@ -91,7 +91,7 @@ func (b *Board) CreatedAt() time.Time {
 // Attributes currently known to be unsupported: idBoardSource, keepFromSource.
 //
 // API Docs: https://developers.trello.com/reference/#boardsid
-func (c *Client) CreateBoard(board *Board, extraArgs Arguments) error {
+func (c *Client) CreateBoard(board *Board, extraArgs ...Arguments) error {
 	path := "boards"
 	args := Arguments{
 		"desc":             board.Desc,
@@ -120,14 +120,7 @@ func (c *Client) CreateBoard(board *Board, extraArgs Arguments) error {
 		args["prefs_cardAging"] = board.Prefs.CardAging
 	}
 
-	// Expects "true" or "false"
-	if defaultLists, ok := extraArgs["defaultLists"]; ok {
-		args["defaultLists"] = defaultLists
-	}
-	// Expects one of "all", "calendar", "cardAging", "recap", or "voting".
-	if powerUps, ok := extraArgs["powerUps"]; ok {
-		args["powerUps"] = powerUps
-	}
+	args.flatten(extraArgs)
 
 	err := c.Post(path, args, &board)
 	if err == nil {
@@ -138,14 +131,16 @@ func (c *Client) CreateBoard(board *Board, extraArgs Arguments) error {
 
 // Update PUTs the supported board attributes remote and updates
 // the struct from the returned values.
-func (b *Board) Update(extraArgs Arguments) error {
-	return b.client.PutBoard(b, extraArgs)
+func (b *Board) Update(extraArgs ...Arguments) error {
+	args := flattenArguments(extraArgs)
+	return b.client.PutBoard(b, args)
 }
 
 // Delete makes a DELETE call for the receiver Board.
-func (b *Board) Delete(extraArgs Arguments) error {
+func (b *Board) Delete(extraArgs ...Arguments) error {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s", b.ID)
-	return b.client.Delete(path, Arguments{}, b)
+	return b.client.Delete(path, args, b)
 }
 
 // AddedMembersResponse represents a response after adding a new member.
@@ -157,18 +152,12 @@ type AddedMembersResponse struct {
 
 // AddMember adds a new member to the board.
 // https://developers.trello.com/reference#boardsidlabelnamesmembers
-func (b *Board) AddMember(member *Member, extraArgs Arguments) (response *AddedMembersResponse, err error) {
+func (b *Board) AddMember(member *Member, extraArgs ...Arguments) (response *AddedMembersResponse, err error) {
 	args := Arguments{
 		"email": member.Email,
 	}
 
-	// "normal" is the default type, so we can omit it.
-	if memberType, ok := extraArgs["type"]; ok {
-		switch memberType {
-		case "admin", "observer":
-			args["type"] = memberType
-		}
-	}
+	args.flatten(extraArgs)
 
 	path := fmt.Sprintf("boards/%s/members", b.ID)
 	err = b.client.Put(path, args, &response)
@@ -176,7 +165,8 @@ func (b *Board) AddMember(member *Member, extraArgs Arguments) (response *AddedM
 }
 
 // GetBoard retrieves a Trello board by its ID.
-func (c *Client) GetBoard(boardID string, args Arguments) (board *Board, err error) {
+func (c *Client) GetBoard(boardID string, extraArgs ...Arguments) (board *Board, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s", boardID)
 	err = c.Get(path, args, &board)
 	if board != nil {
@@ -186,7 +176,8 @@ func (c *Client) GetBoard(boardID string, args Arguments) (board *Board, err err
 }
 
 // GetMyBoards returns a slice of all boards associated with the credentials set on the client.
-func (c *Client) GetMyBoards(args Arguments) (boards []*Board, err error) {
+func (c *Client) GetMyBoards(extraArgs ...Arguments) (boards []*Board, err error) {
+	args := flattenArguments(extraArgs)
 	path := "members/me/boards"
 	err = c.Get(path, args, &boards)
 	for i := range boards {
@@ -196,7 +187,8 @@ func (c *Client) GetMyBoards(args Arguments) (boards []*Board, err error) {
 }
 
 // GetBoards returns a slice of all public boards of the receiver Member.
-func (m *Member) GetBoards(args Arguments) (boards []*Board, err error) {
+func (m *Member) GetBoards(extraArgs ...Arguments) (boards []*Board, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("members/%s/boards", m.ID)
 	err = m.client.Get(path, args, &boards)
 	for i := range boards {
@@ -212,7 +204,7 @@ func (m *Member) GetBoards(args Arguments) (boards []*Board, err error) {
 // PutBoard PUTs a board remote. Extra arguments are currently unsupported.
 //
 // API Docs: https://developers.trello.com/reference#idnext
-func (c *Client) PutBoard(board *Board, extraArgs Arguments) error {
+func (c *Client) PutBoard(board *Board, extraArgs ...Arguments) error {
 	path := fmt.Sprintf("boards/%s", board.ID)
 	args := Arguments{
 		"desc":             board.Desc,
@@ -241,6 +233,8 @@ func (c *Client) PutBoard(board *Board, extraArgs Arguments) error {
 		args["prefs/cardAging"] = board.Prefs.CardAging
 	}
 
+	args.flatten(extraArgs)
+
 	err := c.Put(path, args, &board)
 	if err == nil {
 		board.client = c
diff --git a/card.go b/card.go
index 682f935..a61b298 100644
--- a/card.go
+++ b/card.go
@@ -144,7 +144,8 @@ func (c *Card) CustomFields(boardCustomFields []*CustomField) map[string]interfa
 }
 
 // MoveToList moves a card to a list given by listID.
-func (c *Card) MoveToList(listID string, args Arguments) error {
+func (c *Card) MoveToList(listID string, extraArgs ...Arguments) error {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("cards/%s", c.ID)
 	args["idList"] = listID
 	return c.client.Put(path, args, &c)
@@ -196,7 +197,8 @@ func (c *Card) MoveToBottomOfList() error {
 }
 
 // Update UPDATEs the card's attributes.
-func (c *Card) Update(args Arguments) error {
+func (c *Card) Update(extraArgs ...Arguments) error {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("cards/%s", c.ID)
 	return c.client.Put(path, args, c)
 }
@@ -218,7 +220,7 @@ func (c *Card) Delete() error {
 }
 
 // CreateCard takes a Card and Arguments and POSTs the card.
-func (c *Client) CreateCard(card *Card, extraArgs Arguments) error {
+func (c *Client) CreateCard(card *Card, extraArgs ...Arguments) error {
 	path := "cards"
 	args := Arguments{
 		"name":      card.Name,
@@ -231,10 +233,8 @@ func (c *Client) CreateCard(card *Card, extraArgs Arguments) error {
 	if card.Due != nil {
 		args["due"] = card.Due.Format(time.RFC3339)
 	}
-	// Allow overriding the creation position with 'top' or 'botttom'
-	if pos, ok := extraArgs["pos"]; ok {
-		args["pos"] = pos
-	}
+
+	args.flatten(extraArgs)
 	err := c.Post(path, args, &card)
 	if err == nil {
 		card.client = c
@@ -243,7 +243,7 @@ func (c *Client) CreateCard(card *Card, extraArgs Arguments) error {
 }
 
 // AddCard takes a Card and Arguments and adds the card to the receiver list.
-func (l *List) AddCard(card *Card, extraArgs Arguments) error {
+func (l *List) AddCard(card *Card, extraArgs ...Arguments) error {
 	path := fmt.Sprintf("lists/%s/cards", l.ID)
 	args := Arguments{
 		"name":      card.Name,
@@ -254,10 +254,9 @@ func (l *List) AddCard(card *Card, extraArgs Arguments) error {
 	if card.Due != nil {
 		args["due"] = card.Due.Format(time.RFC3339)
 	}
-	// Allow overwriting the creation position with 'top' or 'bottom'
-	if pos, ok := extraArgs["pos"]; ok {
-		args["pos"] = pos
-	}
+
+	args.flatten(extraArgs)
+
 	err := l.client.Post(path, args, &card)
 	if err == nil {
 		card.client = l.client
@@ -273,11 +272,14 @@ func (l *List) AddCard(card *Card, extraArgs Arguments) error {
 //	Arguments["keepFromSource"] = "all"
 //  Arguments["keepFromSource"] = "none"
 //	Arguments["keepFromSource"] = "attachments,checklists,comments"
-func (c *Card) CopyToList(listID string, args Arguments) (*Card, error) {
+func (c *Card) CopyToList(listID string, extraArgs ...Arguments) (*Card, error) {
+	args := Arguments{
+		"idList":       listID,
+		"idCardSource": c.ID,
+	}
 	path := "cards"
-	args["idList"] = listID
-	args["idCardSource"] = c.ID
 	newCard := Card{}
+	args.flatten(extraArgs)
 	err := c.client.Post(path, args, &newCard)
 	if err == nil {
 		newCard.client = c.client
@@ -288,9 +290,12 @@ func (c *Card) CopyToList(listID string, args Arguments) (*Card, error) {
 }
 
 // AddComment takes a comment string and Arguments and adds the comment to the card.
-func (c *Card) AddComment(comment string, args Arguments) (*Action, error) {
+func (c *Card) AddComment(comment string, extraArgs ...Arguments) (*Action, error) {
+	args := Arguments{
+		"text": comment,
+	}
+	args.flatten(extraArgs)
 	path := fmt.Sprintf("cards/%s/actions/comments", c.ID)
-	args["text"] = comment
 	action := Action{}
 	err := c.client.Post(path, args, &action)
 	if err != nil {
@@ -300,12 +305,13 @@ func (c *Card) AddComment(comment string, args Arguments) (*Action, error) {
 }
 
 // AddURLAttachment takes an Attachment and adds it to the card.
-func (c *Card) AddURLAttachment(attachment *Attachment) error {
+func (c *Card) AddURLAttachment(attachment *Attachment, extraArgs ...Arguments) error {
 	path := fmt.Sprintf("cards/%s/attachments", c.ID)
 	args := Arguments{
 		"url":  attachment.URL,
 		"name": attachment.Name,
 	}
+	args.flatten(extraArgs)
 	err := c.client.Post(path, args, &attachment)
 	if err != nil {
 		err = errors.Wrapf(err, "Error adding attachment to card %s", c.ID)
@@ -318,8 +324,8 @@ func (c *Card) AddURLAttachment(attachment *Attachment) error {
 // from a copy of another Card. Returns an error only when a low-level failure occurred.
 // If this Card has no parent, a nil card and nil error are returned. In other words, the
 // non-existence of a parent is not treated as an error.
-func (c *Card) GetParentCard(args Arguments) (*Card, error) {
-
+func (c *Card) GetParentCard(extraArgs ...Arguments) (*Card, error) {
+	args := flattenArguments(extraArgs)
 	// Hopefully the card came pre-loaded with Actions including the card creation
 	action := c.Actions.FirstCardCreateAction()
 
@@ -343,8 +349,8 @@ func (c *Card) GetParentCard(args Arguments) (*Card, error) {
 }
 
 // GetAncestorCards takes Arguments, GETs the card's ancestors and returns them as a slice.
-func (c *Card) GetAncestorCards(args Arguments) (ancestors []*Card, err error) {
-
+func (c *Card) GetAncestorCards(extraArgs ...Arguments) (ancestors []*Card, err error) {
+	args := flattenArguments(extraArgs)
 	// Get the first parent
 	parent, err := c.GetParentCard(args)
 	if IsNotFound(err) || IsPermissionDenied(err) {
@@ -367,7 +373,8 @@ func (c *Card) GetAncestorCards(args Arguments) (ancestors []*Card, err error) {
 }
 
 // GetOriginatingCard takes Arguments, GETs ancestors and returns most recent ancestor card of the Card.
-func (c *Card) GetOriginatingCard(args Arguments) (*Card, error) {
+func (c *Card) GetOriginatingCard(extraArgs ...Arguments) (*Card, error) {
+	args := flattenArguments(extraArgs)
 	ancestors, err := c.GetAncestorCards(args)
 	if err != nil {
 		return c, err
@@ -427,8 +434,11 @@ func (c *Card) CreatorMemberID() (string, error) {
 
 // ContainsCopyOfCard accepts a card id and Arguments and returns true
 // if the receiver Board contains a Card with the id.
-func (b *Board) ContainsCopyOfCard(cardID string, args Arguments) (bool, error) {
-	args["filter"] = "copyCard"
+func (b *Board) ContainsCopyOfCard(cardID string, extraArgs ...Arguments) (bool, error) {
+	args := Arguments{
+		"filter": "copyCard",
+	}
+	args.flatten(extraArgs)
 	actions, err := b.GetActions(args)
 	if err != nil {
 		err := errors.Wrapf(err, "GetCards() failed inside ContainsCopyOf() for board '%s' and card '%s'.", b.ID, cardID)
@@ -445,7 +455,8 @@ func (b *Board) ContainsCopyOfCard(cardID string, args Arguments) (bool, error)
 // GetCard receives a card id and Arguments and returns the card if found
 // with the credentials given for the receiver Client. Returns an error
 // otherwise.
-func (c *Client) GetCard(cardID string, args Arguments) (card *Card, err error) {
+func (c *Client) GetCard(cardID string, extraArgs ...Arguments) (card *Card, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("cards/%s", cardID)
 	err = c.Get(path, args, &card)
 	if card != nil {
@@ -455,7 +466,8 @@ func (c *Client) GetCard(cardID string, args Arguments) (card *Card, err error)
 }
 
 // GetCards takes Arguments and retrieves all Cards on a Board as slice or returns error.
-func (b *Board) GetCards(args Arguments) (cards []*Card, err error) {
+func (b *Board) GetCards(extraArgs ...Arguments) (cards []*Card, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/cards", b.ID)
 
 	err = b.client.Get(path, args, &cards)
@@ -484,7 +496,8 @@ func (b *Board) GetCards(args Arguments) (cards []*Card, err error) {
 }
 
 // GetCards retrieves all Cards in a List or an error if something goes wrong.
-func (l *List) GetCards(args Arguments) (cards []*Card, err error) {
+func (l *List) GetCards(extraArgs ...Arguments) (cards []*Card, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("lists/%s/cards", l.ID)
 	err = l.client.Get(path, args, &cards)
 	for i := range cards {
diff --git a/checklist.go b/checklist.go
index 7ef018a..1fbc0cc 100644
--- a/checklist.go
+++ b/checklist.go
@@ -5,6 +5,8 @@
 
 package trello
 
+import "fmt"
+
 // Checklist represents Trello card's checklists.
 // A card can have one zero or more checklists.
 // https://developers.trello.com/reference/#checklist-object
@@ -38,16 +40,14 @@ type CheckItemState struct {
 // Attributes currently known to be unsupported: idChecklistSource.
 //
 // API Docs: https://developers.trello.com/reference#cardsidchecklists-1
-func (c *Client) CreateChecklist(card *Card, name string, extraArgs Arguments) (checklist *Checklist, err error) {
+func (c *Client) CreateChecklist(card *Card, name string, extraArgs ...Arguments) (checklist *Checklist, err error) {
 	path := "cards/" + card.ID + "/checklists"
 	args := Arguments{
 		"name": name,
 		"pos":  "bottom",
 	}
 
-	if pos, ok := extraArgs["pos"]; ok {
-		args["pos"] = pos
-	}
+	args.flatten(extraArgs)
 
 	checklist = &Checklist{}
 	err = c.Post(path, args, &checklist)
@@ -64,8 +64,9 @@ func (c *Client) CreateChecklist(card *Card, name string, extraArgs Arguments) (
 // Attributes currently known to be unsupported: checked.
 //
 // API Docs: https://developers.trello.com/reference#checklistsidcheckitems
-func (cl *Checklist) CreateCheckItem(name string, extraArgs Arguments) (item *CheckItem, err error) {
-	return cl.client.CreateCheckItem(cl, name, extraArgs)
+func (cl *Checklist) CreateCheckItem(name string, extraArgs ...Arguments) (item *CheckItem, err error) {
+	args := flattenArguments(extraArgs)
+	return cl.client.CreateCheckItem(cl, name, args)
 }
 
 // CreateCheckItem creates a checkitem inside the given checklist.
@@ -73,7 +74,7 @@ func (cl *Checklist) CreateCheckItem(name string, extraArgs Arguments) (item *Ch
 // Attributes currently known to be unsupported: checked.
 //
 // API Docs: https://developers.trello.com/reference#checklistsidcheckitems
-func (c *Client) CreateCheckItem(checklist *Checklist, name string, extraArgs Arguments) (item *CheckItem, err error) {
+func (c *Client) CreateCheckItem(checklist *Checklist, name string, extraArgs ...Arguments) (item *CheckItem, err error) {
 	path := "checklists/" + checklist.ID + "/checkItems"
 	args := Arguments{
 		"name":    name,
@@ -81,12 +82,7 @@ func (c *Client) CreateCheckItem(checklist *Checklist, name string, extraArgs Ar
 		"checked": "false",
 	}
 
-	if pos, ok := extraArgs["pos"]; ok {
-		args["pos"] = pos
-	}
-	if checked, ok := extraArgs["checked"]; ok {
-		args["checked"] = checked
-	}
+	args.flatten(extraArgs)
 
 	item = &CheckItem{}
 	err = c.Post(path, args, item)
@@ -95,3 +91,15 @@ func (c *Client) CreateCheckItem(checklist *Checklist, name string, extraArgs Ar
 	}
 	return
 }
+
+// GetChecklist receives a checklist id and Arguments and returns the checklist if found
+// with the credentials given for the receiver Client. Returns an error
+// otherwise.
+func (c *Client) GetChecklist(checklistID string, args Arguments) (checklist *Checklist, err error) {
+	path := fmt.Sprintf("checklists/%s", checklistID)
+	err = c.Get(path, args, &checklist)
+	if checklist != nil {
+		checklist.client = c
+	}
+	return checklist, err
+}
diff --git a/checklist_test.go b/checklist_test.go
index 3777b15..160c5a0 100644
--- a/checklist_test.go
+++ b/checklist_test.go
@@ -91,3 +91,42 @@ func TestCreateCheckItem(t *testing.T) {
 		t.Errorf("Expected checked to be set. Instead got '%s'.", item.State)
 	}
 }
+
+func TestGetChecklist(t *testing.T) {
+	checklist := testChecklist(t)
+	if checklist.Name != "Example checklist" {
+		t.Errorf("Name incorrect. Got '%s'", checklist.Name)
+	}
+
+	if checklist.Pos != 1 {
+		t.Errorf("Pos incorrect. Got '%0.2f'", checklist.Pos)
+	}
+
+	if len(checklist.CheckItems) != 1 {
+		t.Errorf("len(checklist.CheckItems) incorrect. Got '%0.2f'", checklist.Pos)
+	}
+
+	if checklist.CheckItems[0].Name != "Example checkItem" {
+		t.Errorf("CheckItem Name incorrect. Got '%s'", checklist.CheckItems[0].Name)
+	}
+
+	if checklist.CheckItems[0].State != "complete" {
+		t.Errorf("CheckItem State incorrect. Got '%s'", checklist.CheckItems[0].State)
+	}
+
+	if checklist.CheckItems[0].Pos != 2 {
+		t.Errorf("CheckItem Pos incorrect. Got '%0.2f'", checklist.CheckItems[0].Pos)
+	}
+}
+
+// Utility function to get a simple response from Client.GetChecklist()
+//
+func testChecklist(t *testing.T) *Checklist {
+	c := testClient()
+	c.BaseURL = mockResponse("checklists", "checklist-api-example.json").URL
+	checklist, err := c.GetChecklist("4eea503", Defaults())
+	if err != nil {
+		t.Fatal(err)
+	}
+	return checklist
+}
diff --git a/client.go b/client.go
index 3129faa..02a8b9b 100644
--- a/client.go
+++ b/client.go
@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
+	"golang.org/x/time/rate"
 )
 
 // DefaultBaseURL is the default API base url used by Client to send requests to Trello.
@@ -27,7 +28,7 @@ type Client struct {
 	BaseURL  string
 	Key      string
 	Token    string
-	throttle <-chan time.Time
+	throttle *rate.Limiter
 	testMode bool
 	ctx      context.Context
 }
@@ -39,12 +40,14 @@ type logger interface {
 // NewClient is a constructor for the Client. It takes the key and token credentials
 // of a Trello member to authenticate and authorise requests with.
 func NewClient(key, token string) *Client {
+	limit := rate.Every(time.Second / 8) // Actually 10/second, but we're extra cautious
+
 	return &Client{
 		Client:   http.DefaultClient,
 		BaseURL:  DefaultBaseURL,
 		Key:      key,
 		Token:    token,
-		throttle: time.Tick(time.Second / 8), // Actually 10/second, but we're extra cautious
+		throttle: rate.NewLimiter(limit, 1),
 		testMode: false,
 		ctx:      context.Background(),
 	}
@@ -61,7 +64,7 @@ func (c *Client) WithContext(ctx context.Context) *Client {
 // Throttle starts receiving throttles from throttle channel each ticker period.
 func (c *Client) Throttle() {
 	if !c.testMode {
-		<-c.throttle
+		c.throttle.Wait(c.ctx)
 	}
 }
 
diff --git a/custom-fields.go b/custom-fields.go
index 05d19ec..b0852e7 100644
--- a/custom-fields.go
+++ b/custom-fields.go
@@ -144,14 +144,16 @@ type CustomFieldOption struct {
 }
 
 // GetCustomField takes a field id string and Arguments and returns the matching custom Field.
-func (c *Client) GetCustomField(fieldID string, args Arguments) (customField *CustomField, err error) {
+func (c *Client) GetCustomField(fieldID string, extraArgs ...Arguments) (customField *CustomField, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("customFields/%s", fieldID)
 	err = c.Get(path, args, &customField)
 	return
 }
 
 // GetCustomFields returns a slice of all receiver board's custom fields.
-func (b *Board) GetCustomFields(args Arguments) (customFields []*CustomField, err error) {
+func (b *Board) GetCustomFields(extraArgs ...Arguments) (customFields []*CustomField, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/customFields", b.ID)
 	err = b.client.Get(path, args, &customFields)
 	return
diff --git a/go.mod b/go.mod
index 2c4bb0a..a33a592 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,7 @@ module github.com/adlio/trello
 
 go 1.13
 
-require github.com/pkg/errors v0.8.1
+require (
+	github.com/pkg/errors v0.8.1
+	golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e
+)
diff --git a/go.sum b/go.sum
index f29ab35..b3b14f0 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,4 @@
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e h1:EHBhcS0mlXEAVwNyO2dLfjToGsyY4j24pTs2ScHnX7s=
+golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
diff --git a/label.go b/label.go
index 4d3155f..d413ab8 100644
--- a/label.go
+++ b/label.go
@@ -20,14 +20,16 @@ type Label struct {
 
 // GetLabel takes a label id and Arguments and returns the matching label (per Trello member)
 // or an error.
-func (c *Client) GetLabel(labelID string, args Arguments) (label *Label, err error) {
+func (c *Client) GetLabel(labelID string, extraArgs ...Arguments) (label *Label, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("labels/%s", labelID)
 	err = c.Get(path, args, &label)
 	return
 }
 
 // GetLabels takes Arguments and returns a slice containing all labels of the receiver board or an error.
-func (b *Board) GetLabels(args Arguments) (labels []*Label, err error) {
+func (b *Board) GetLabels(extraArgs ...Arguments) (labels []*Label, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/labels", b.ID)
 	err = b.client.Get(path, args, &labels)
 	return
diff --git a/list.go b/list.go
index 3b28b7f..83aadc4 100644
--- a/list.go
+++ b/list.go
@@ -31,7 +31,8 @@ func (l *List) CreatedAt() time.Time {
 }
 
 // GetList takes a list's id and Arguments and returns the matching list.
-func (c *Client) GetList(listID string, args Arguments) (list *List, err error) {
+func (c *Client) GetList(listID string, extraArgs ...Arguments) (list *List, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("lists/%s", listID)
 	err = c.Get(path, args, &list)
 	if list != nil {
@@ -44,7 +45,8 @@ func (c *Client) GetList(listID string, args Arguments) (list *List, err error)
 }
 
 // GetLists takes Arguments and returns the lists of the receiver Board.
-func (b *Board) GetLists(args Arguments) (lists []*List, err error) {
+func (b *Board) GetLists(extraArgs ...Arguments) (lists []*List, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/lists", b.ID)
 	err = b.client.Get(path, args, &lists)
 	for i := range lists {
@@ -61,7 +63,7 @@ func (b *Board) GetLists(args Arguments) (lists []*List, err error) {
 // Attributes currently known to be unsupported: idListSource.
 //
 // API Docs: https://developers.trello.com/reference/#lists-1
-func (c *Client) CreateList(onBoard *Board, name string, extraArgs Arguments) (list *List, err error) {
+func (c *Client) CreateList(onBoard *Board, name string, extraArgs ...Arguments) (list *List, err error) {
 	path := "lists"
 	args := Arguments{
 		"name":    name,
@@ -69,9 +71,7 @@ func (c *Client) CreateList(onBoard *Board, name string, extraArgs Arguments) (l
 		"idBoard": onBoard.ID,
 	}
 
-	if pos, ok := extraArgs["pos"]; ok {
-		args["pos"] = pos
-	}
+	args.flatten(extraArgs)
 
 	list = &List{}
 	err = c.Post(path, args, &list)
@@ -86,13 +86,15 @@ func (c *Client) CreateList(onBoard *Board, name string, extraArgs Arguments) (l
 // Attributes currently known to be unsupported: idListSource.
 //
 // API Docs: https://developers.trello.com/reference/#lists-1
-func (b *Board) CreateList(name string, extraArgs Arguments) (list *List, err error) {
-	return b.client.CreateList(b, name, extraArgs)
+func (b *Board) CreateList(name string, extraArgs ...Arguments) (list *List, err error) {
+	args := flattenArguments(extraArgs)
+	return b.client.CreateList(b, name, args)
 }
 
 // Update UPDATEs the list's attributes.
 // API Docs: https://developers.trello.com/reference/#listsid-1
-func (l *List) Update(args Arguments) error {
+func (l *List) Update(extraArgs ...Arguments) error {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("lists/%s", l.ID)
 	return l.client.Put(path, args, l)
 }
diff --git a/member.go b/member.go
index 40f2965..57e40ef 100644
--- a/member.go
+++ b/member.go
@@ -12,17 +12,20 @@ import (
 // Member represents a Trello member.
 // https://developers.trello.com/reference/#member-object
 type Member struct {
-	client     *Client
-	ID         string `json:"id"`
-	Username   string `json:"username"`
-	FullName   string `json:"fullName"`
-	Initials   string `json:"initials"`
-	AvatarHash string `json:"avatarHash"`
-	Email      string `json:"email"`
+	client          *Client
+	ID              string   `json:"id"`
+	Username        string   `json:"username"`
+	FullName        string   `json:"fullName"`
+	Initials        string   `json:"initials"`
+	AvatarHash      string   `json:"avatarHash"`
+	Email           string   `json:"email"`
+	IDBoards        []string `json:"idBoards"`
+	IDOrganizations []string `json:"idOrganizations"`
 }
 
 // GetMember takes a member id and Arguments and returns a Member or an error.
-func (c *Client) GetMember(memberID string, args Arguments) (member *Member, err error) {
+func (c *Client) GetMember(memberID string, extraArgs ...Arguments) (member *Member, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("members/%s", memberID)
 	err = c.Get(path, args, &member)
 	if err == nil {
@@ -31,8 +34,19 @@ func (c *Client) GetMember(memberID string, args Arguments) (member *Member, err
 	return
 }
 
+// GetMyMember returns Member for the user authenticating the API call
+func (c *Client) GetMyMember(args Arguments) (member *Member, err error) {
+	path := fmt.Sprintf("members/me")
+	err = c.Get(path, args, &member)
+	if err == nil {
+		member.client = c
+	}
+	return
+}
+
 // GetMembers takes Arguments and returns a slice of all members of the organization or an error.
-func (o *Organization) GetMembers(args Arguments) (members []*Member, err error) {
+func (o *Organization) GetMembers(extraArgs ...Arguments) (members []*Member, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("organizations/%s/members", o.ID)
 	err = o.client.Get(path, args, &members)
 	for i := range members {
@@ -42,7 +56,8 @@ func (o *Organization) GetMembers(args Arguments) (members []*Member, err error)
 }
 
 // GetMembers takes Arguments and returns a slice of all members of the Board or an error.
-func (b *Board) GetMembers(args Arguments) (members []*Member, err error) {
+func (b *Board) GetMembers(extraArgs ...Arguments) (members []*Member, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("boards/%s/members", b.ID)
 	err = b.client.Get(path, args, &members)
 	for i := range members {
@@ -52,7 +67,8 @@ func (b *Board) GetMembers(args Arguments) (members []*Member, err error) {
 }
 
 // GetMembers takes Arguments and returns a slice of all members of the Card or an error.
-func (c *Card) GetMembers(args Arguments) (members []*Member, err error) {
+func (c *Card) GetMembers(extraArgs ...Arguments) (members []*Member, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("cards/%s/members", c.ID)
 	err = c.client.Get(path, args, &members)
 	for i := range members {
diff --git a/notification.go b/notification.go
index d2ae4b2..641583d 100644
--- a/notification.go
+++ b/notification.go
@@ -43,7 +43,8 @@ type NotificationDataCard struct {
 }
 
 // GetMyNotifications returns the notifications of the authenticated user
-func (c *Client) GetMyNotifications(args Arguments) (notifications []*Notification, err error) {
+func (c *Client) GetMyNotifications(extraArgs ...Arguments) (notifications []*Notification, err error) {
+	args := flattenArguments(extraArgs)
 	path := "members/me/notifications"
 	err = c.Get(path, args, &notifications)
 	for i := range notifications {
diff --git a/organization.go b/organization.go
index 3c46f77..12669a9 100644
--- a/organization.go
+++ b/organization.go
@@ -25,7 +25,8 @@ type Organization struct {
 
 // GetOrganization takes an organization id and Arguments and either
 // GETs returns an Organization, or an error.
-func (c *Client) GetOrganization(orgID string, args Arguments) (organization *Organization, err error) {
+func (c *Client) GetOrganization(orgID string, extraArgs ...Arguments) (organization *Organization, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("organizations/%s", orgID)
 	err = c.Get(path, args, &organization)
 	if organization != nil {
diff --git a/search.go b/search.go
index 386039b..bc98a03 100644
--- a/search.go
+++ b/search.go
@@ -35,9 +35,12 @@ type SearchTerm struct {
 }
 
 // SearchCards takes a query string and Arguments and returns a slice of Cards or an error.
-func (c *Client) SearchCards(query string, args Arguments) (cards []*Card, err error) {
-	args["query"] = query
-	args["modelTypes"] = "cards"
+func (c *Client) SearchCards(query string, extraArgs ...Arguments) (cards []*Card, err error) {
+	args := Arguments{
+		"query":      query,
+		"modelTypes": "cards",
+	}
+	args.flatten(extraArgs)
 	res := SearchResult{}
 	err = c.Get("search", args, &res)
 	cards = res.Cards
@@ -48,9 +51,12 @@ func (c *Client) SearchCards(query string, args Arguments) (cards []*Card, err e
 }
 
 // SearchBoards takes a query string and Arguments and returns a slice of Boards or an error.
-func (c *Client) SearchBoards(query string, args Arguments) (boards []*Board, err error) {
-	args["query"] = query
-	args["modelTypes"] = "boards"
+func (c *Client) SearchBoards(query string, extraArgs ...Arguments) (boards []*Board, err error) {
+	args := Arguments{
+		"query":      query,
+		"modelTypes": "boards",
+	}
+	args.flatten(extraArgs)
 	res := SearchResult{}
 	err = c.Get("search", args, &res)
 	boards = res.Boards
@@ -61,8 +67,11 @@ func (c *Client) SearchBoards(query string, args Arguments) (boards []*Board, er
 }
 
 // SearchMembers takes a query string and Arguments and returns a slice of Members or an error.
-func (c *Client) SearchMembers(query string, args Arguments) (members []*Member, err error) {
-	args["query"] = query
+func (c *Client) SearchMembers(query string, extraArgs ...Arguments) (members []*Member, err error) {
+	args := Arguments{
+		"query": query,
+	}
+	args.flatten(extraArgs)
 	err = c.Get("search/members", args, &members)
 	return
 }
diff --git a/testdata/checklists/checklist-api-example.json b/testdata/checklists/checklist-api-example.json
new file mode 100644
index 0000000..fd0bdbf
--- /dev/null
+++ b/testdata/checklists/checklist-api-example.json
@@ -0,0 +1,21 @@
+{
+    "id": "333333333333333333333333",
+    "name": "Example checklist",
+    "idCard": "222222222222222222222222",
+    "pos": 1,
+    "idBoard": "111111111111111111111111",
+    "checkItems": [
+        {
+            "idChecklist": "444444444444444444444444",
+            "state": "complete",
+            "idMember": null,
+            "id": "555555555555555555555555",
+            "name": "Example checkItem",
+            "nameData": {
+                "emoji": {}
+            },
+            "pos": 2,
+            "due": null
+        }
+    ]
+}
\ No newline at end of file
diff --git a/token.go b/token.go
index af9ad4b..ea7e7c7 100644
--- a/token.go
+++ b/token.go
@@ -31,7 +31,8 @@ type Permission struct {
 }
 
 // GetToken takes a token id and Arguments and GETs and returns the Token or an error.
-func (c *Client) GetToken(tokenID string, args Arguments) (token *Token, err error) {
+func (c *Client) GetToken(tokenID string, extraArgs ...Arguments) (token *Token, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("tokens/%s", tokenID)
 	err = c.Get(path, args, &token)
 	if token != nil {
diff --git a/webhook.go b/webhook.go
index 2753cab..182a670 100644
--- a/webhook.go
+++ b/webhook.go
@@ -62,13 +62,14 @@ func (c *Client) CreateWebhook(webhook *Webhook) error {
 }
 
 // Delete takes a webhook and deletes it
-func (w *Webhook) Delete(args Arguments) error {
+func (w *Webhook) Delete(extraArgs ...Arguments) error {
 	path := fmt.Sprintf("webhooks/%s", w.ID)
 	return w.client.Delete(path, Arguments{}, w)
 }
 
 // GetWebhook takes a webhook id and Arguments, GETs the matching Webhook and returns it or an error.
-func (c *Client) GetWebhook(webhookID string, args Arguments) (webhook *Webhook, err error) {
+func (c *Client) GetWebhook(webhookID string, extraArgs ...Arguments) (webhook *Webhook, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("webhooks/%s", webhookID)
 	err = c.Get(path, args, &webhook)
 	if webhook != nil {
@@ -78,7 +79,8 @@ func (c *Client) GetWebhook(webhookID string, args Arguments) (webhook *Webhook,
 }
 
 // GetWebhooks takes Arguments and returns a list of all Webhooks for the receiver Token or an error.
-func (t *Token) GetWebhooks(args Arguments) (webhooks []*Webhook, err error) {
+func (t *Token) GetWebhooks(extraArgs ...Arguments) (webhooks []*Webhook, err error) {
+	args := flattenArguments(extraArgs)
 	path := fmt.Sprintf("tokens/%s/webhooks", t.client.Token)
 	err = t.client.Get(path, args, &webhooks)
 	if err == nil {