code: def _export_python(self, filename, **kwargs):
          
          data = dict(grid=self.grid, edges=self.edges, metadata=self.metadata)
          with open(filename, 'wb') as f:
              cPickle.dump(data, f, cPickle.HIGHEST_PROTOCOL)
docs: Pickle the Grid object
  
          The object is dumped as a dictionary with grid and edges: This
          is sufficient to recreate the grid object with __init__().