diff --git a/treemanifest/__init__.py b/treemanifest/__init__.py
--- a/treemanifest/__init__.py
+++ b/treemanifest/__init__.py
@@ -1820,6 +1820,8 @@
             f.write(sha)
             f.write(value)
 
+        # Expire cache if it's too large
+
     def getnodeinfo(self, name, node):
         key = self._key(name, node, 'nodeinfo')
         try: