diff --git a/stdlib/3/collections/__init__.pyi b/stdlib/3/collections/__init__.pyi
index 0f059ec3d..328644412 100644
--- a/stdlib/3/collections/__init__.pyi
+++ b/stdlib/3/collections/__init__.pyi
@@ -180,3 +180,9 @@ if sys.version_info >= (3, 3):
 
         @property
         def parents(self) -> ChainMap[_KT, _VT]: ...
+
+        def __setitem__(self, k: _KT, v: _VT) -> None: ...
+        def __delitem__(self, v: _KT) -> None: ...
+        def __getitem__(self, k: _KT) -> _VT: ...
+        def __iter__(self) -> Iterator[_KT]: ...
+        def __len__(self) -> int: ...