code: def _global_var_name(splittable_dimension, mesh_dimension):
      """Name for a global variable.
  
      Args:
        splittable_dimension: the name of a splittable dimension (string)
        mesh_dimension: the name of a mesh dimension (string)
  
      Returns:
        A string, the variable name.
      """
      return "x_({}:{})".format(splittable_dimension, mesh_dimension)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import itertools
  from absl import logging
  from mesh_tensorflow.auto_mtf import print_cp_model_solution
  from mesh_tensorflow.auto_mtf import scheduler
  import six
  from ortools.sat.python import cp_model
label_desc: Use image node_id 1 for calling a global function with example usage: _global_var_name(splittable_dimension, mesh_dimension) and returns: str