diff -r 67714c4d9725 Lib/filecmp.py
--- a/Lib/filecmp.py	Mon Jun 10 23:02:56 2013 -0500
+++ b/Lib/filecmp.py	Wed Jun 12 13:47:10 2013 +0100
@@ -6,6 +6,7 @@
 Functions:
     cmp(f1, f2, shallow=True) -> int
     cmpfiles(a, b, common) -> ([], [], [])
+    clear_cache()
 
 """
 
@@ -21,6 +22,11 @@
 DEFAULT_IGNORES = [
     'RCS', 'CVS', 'tags', '.git', '.hg', '.bzr', '_darcs', '__pycache__']
 
+def clear_cache():
+    """Clear the filecmp cache
+    
+    """
+    _cache.clear()
 
 def cmp(f1, f2, shallow=True):
     """Compare two files.
@@ -39,7 +45,8 @@
     True if the files are the same, False otherwise.
 
     This function uses a cache for past comparisons and the results,
-    with a cache invalidation mechanism relying on stale signatures.
+    with a cache invalidation mechanism relying on stale signatures 
+    or by explicitly calling clear_cache()
 
     """