Fix KeyError in HyperDatabase when checking parentID in articleIndex

Add __contains__ method to DumbBTree class to properly handle 'in'
operator checks. Previously, when parentID was 0 (or any value not
in the index), Python would fall back to __getitem__ which raised
KeyError. Now __contains__ returns False for missing keys instead
of raising an exception.

Author: jared mauch

Mailman/Archiver/HyperDatabase.py

@@ -148,6 +148,9 @@ def __next__(self):
     def has_key(self, key):
         return key in self.dict
 
+    def __contains__(self, key):
+        return key in self.dict
+
     def set_location(self, loc):
         index = 0
         self.__sort()