code: def override_plasticity_state(self, new_plasticity_state):
          
          self._plasticity_setting_stack.append(self.plastic)
          self.plastic=new_plasticity_state
docs: Temporarily disable plasticity of internal state.
  
          This function should be implemented by all subclasses so that
          after a call, the output should always be the same for any
          given input pattern, and no call should have any effect that
          persists after restore_plasticity_state() is called.
  
          By default, simply saves a copy of the 'plastic' parameter to
          an internal stack (so that it can be restored by
          restore_plasticity_state()), and then sets the plastic
          parameter to the given value (True or False).