diff --git a/Lib/fnmatch.py b/Lib/fnmatch.py
index b1c37f5..ffe99b5 100644
--- a/Lib/fnmatch.py
+++ b/Lib/fnmatch.py
@@ -12,11 +12,15 @@
 
 import re
 
-__all__ = ["filter", "fnmatch","fnmatchcase","translate"]
+__all__ = ["filter", "fnmatch", "fnmatchcase", "translate"]
 
 _cache = {}
 _MAXCACHE = 100
 
+def _purge():
+    """Clear the pattern cache"""
+    _cache.clear()
+
 def fnmatch(name, pat):
     """Test whether FILENAME matches PATTERN.