diff --git a/Pipfile b/Pipfile
index 047f246..d2fee92 100644
--- a/Pipfile
+++ b/Pipfile
@@ -13,6 +13,7 @@ black = "*"
 pypd = "*"
 
 [dev-packages]
+sphinx = "*"
 
 [requires]
 python_version = "3.9"