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Lib/functools.py

@@ -141,7 +141,7 @@ def lru_cache(maxsize=100):
 
         hits = misses = 0
         kwd_mark = object()             # separates positional and keyword args
-        lock = Lock()
+        lock = Lock()                   # needed because ordereddicts aren't threadsafe
 
         if maxsize is None:
             cache = dict()              # simple cache without ordering or size limit