code: def _save_impl(self, pickler):
          
          pickler.dump( (self.__proxy__.state, self._exclude, self._features) )
docs: Save the model as a directory, which can be loaded with the
          :py:func:`~turicreate.load_model` method.
  
          Parameters
          ----------
          pickler : GLPickler
              An opened GLPickle archive (Do not close the archive).
  
          See Also
          --------
          turicreate.load_model
  
          Examples
          --------
          >>> model.save('my_model_file')
          >>> loaded_model = turicreate.load_model('my_model_file')