code: def rec_update(self, other, **third):
          
          try:
              iterator = other.iteritems()
          except AttributeError:
              iterator = other
          self.iter_rec_update(iterator)
          self.iter_rec_update(third.iteritems())
docs: Recursively update the dictionary with the contents of other and
          third like dict.update() does - but don't overwrite sub-dictionaries.
          Example:
          >>> d = RecursiveDictionary({'foo': {'bar': 42}})
          >>> d.rec_update({'foo': {'baz': 36}})
          >>> d
          {'foo': {'baz': 36, 'bar': 42}}