Added clear cache methods to clear the internal type lookup cache for ref leak test runs.
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 4b2ff4a..7c88251 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -58,6 +58,13 @@
A string containing the copyright pertaining to the Python interpreter.
+.. function:: _cleartypecache()
+
+ Clear the internal type lookup cache.
+
+ .. versionadded:: 2.6
+
+
.. function:: _current_frames()
Return a dictionary mapping each thread's identifier to the topmost stack frame