code: def _initialize_mtf_dimension_name_to_size_gcd(self, mtf_graph):
      
      mtf_dimension_name_to_size_gcd = {}
      for mtf_operation in mtf_graph.operations:
        for mtf_tensor in mtf_operation.outputs:
          for mtf_dimension in mtf_tensor.shape.dims:
            mtf_dimension_name_to_size_gcd[mtf_dimension.name] = fractions.gcd(
                mtf_dimension_name_to_size_gcd.get(mtf_dimension.name,
                                                   mtf_dimension.size),
                mtf_dimension.size)
  
      return mtf_dimension_name_to_size_gcd
docs: Initializer for self._mtf_dimension_name_to_size_gcd.
  
      Args:
        mtf_graph: an mtf.Graph.
  
      Returns:
        A {string: int}, mapping the name of an MTF dimension to the greatest
        common divisor of all the sizes it has. All these sizes being evenly
        divisible by some x is equivalent to the GCD being divisible by x.