diff --git a/.formatter.exs b/.formatter.exs
index fe7b600..1e9df39 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,5 +1,14 @@
 # Used by "mix format"
+locals_without_parens = [
+  polymorphic_embeds_one: 2,
+  polymorphic_embeds_many: 2
+]
+
 [
   import_deps: [:ecto],
-  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
+  locals_without_parens: locals_without_parens,
+  export: [
+    locals_without_parens: locals_without_parens
+  ]
 ]