1  class ESC[4;38;5;81mDelegator:
       2  
       3      def __init__(self, delegate=None):
       4          self.delegate = delegate
       5          self.__cache = set()
       6          # Cache is used to only remove added attributes
       7          # when changing the delegate.
       8  
       9      def __getattr__(self, name):
      10          attr = getattr(self.delegate, name) # May raise AttributeError
      11          setattr(self, name, attr)
      12          self.__cache.add(name)
      13          return attr
      14  
      15      def resetcache(self):
      16          "Removes added attributes while leaving original attributes."
      17          # Function is really about resetting delegator dict
      18          # to original state.  Cache is just a means
      19          for key in self.__cache:
      20              try:
      21                  delattr(self, key)
      22              except AttributeError:
      23                  pass
      24          self.__cache.clear()
      25  
      26      def setdelegate(self, delegate):
      27          "Reset attributes and change delegate."
      28          self.resetcache()
      29          self.delegate = delegate
      30  
      31  if __name__ == '__main__':
      32      from unittest import main
      33      main('idlelib.idle_test.test_delegator', verbosity=2)