code: def apply_cut(self, cut):
          
          return Subsystem(self.network, self.state, self.node_indices,
                           cut=cut, mice_cache=self._mice_cache)
docs: Return a cut version of this |Subsystem|.
  
          Args:
              cut (Cut): The cut to apply to this |Subsystem|.
  
          Returns:
              Subsystem: The cut subsystem.