code: def is_equivalent(self, callback, details_filter=None):
          
          cb = self.callback
          if cb is None and callback is not None:
              return False
          if cb is not None and callback is None:
              return False
          if cb is not None and callback is not None \
             and not reflection.is_same_callback(cb, callback):
              return False
          if details_filter is not None:
              if self._details_filter is None:
                  return False
              else:
                  return reflection.is_same_callback(self._details_filter,
                                                     details_filter)
          else:
              return self._details_filter is None
docs: Check if the callback provided is the same as the internal one.
  
          :param callback: callback used for comparison
          :param details_filter: callback used for comparison
          :returns: false if not the same callback, otherwise true
          :rtype: boolean