Rename .py to .pyi.

2.7/xxsubtype.pyi

@@ -0,0 +1,19 @@
+"""Stub file for the 'xxsubtype' module."""
+# This is an autogenerated file. It serves as a starting point
+# for a more precise manual annotation of this module.
+# Feel free to edit the source below, but remove this header when you do.
+
+from typing import List, Tuple, Dict, Undefined, GenericType
+
+def bench(a, b: str, *args, **kwargs) -> float: ...
+
+
+class spamdict(object):
+    def getstate() -> int: ...
+    def setstate(a: int) -> None: ...
+
+class spamlist(object):
+    def classmeth(*args, **kwargs) -> tuple: ...
+    def getstate() -> int: ...
+    def setstate(a: int) -> None: ...
+    def staticmeth(*args, **kwargs) -> tuple: ...