"""
  variable_nodes = {}

  for var_node in filter(_is_variable, graph_def.node):
    shared_name = str(var_node.attr['shared_name'].s, encoding='utf-8')
    variable_nodes[shared_name] = var_node

  for func in graph_def.library.function:
    for var_node in filter(_is_variable, func.node_def):
      variable_nodes[shared_name] = var_node

  return variable_nodes