code: def is_valid_assignment(self, mtf_dimension_name, mesh_dimension_name):
      
      return ((mtf_dimension_name in self._splittable_mtf_dimension_names) and
              (self._mtf_dimension_name_to_size_gcd[mtf_dimension_name] %
               self._mesh_dimension_name_to_size[mesh_dimension_name] == 0))
docs: Whether this MTF dimension may be assigned to this mesh dimension.
  
      Args:
        mtf_dimension_name: string, the name of a Mesh TensorFlow dimension.
        mesh_dimension_name: string, the name of a mesh dimension.
  
      Returns:
        A boolean indicating whether the assignment is valid.