code: def _get_global_step_read(graph=None):
      """Gets global step read tensor in graph.
  
      Args:
        graph: The graph in which to create the global step read tensor. If missing,
          use default graph.
  
      Returns:
        Global step read tensor.
  
      Raises:
        RuntimeError: if multiple items found in collection GLOBAL_STEP_READ_KEY.
      """
      graph = graph or ops.get_default_graph()
      global_step_read_tensors = graph.get_collection(
          GLOBAL_STEP_READ_KEY
      )
      if len(global_step_read_tensors) > 1:
          raise RuntimeError(
              "There are multiple items in collection {}. "
              "There should be only one.".format(GLOBAL_STEP_READ_KEY)
          )
  
      if len(global_step_read_tensors) == 1:
          return global_step_read_tensors[0]
      return None
  
imports: from tensorflow.python.eager import context
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import graph_io
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.ops import cond
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import resource_variable_ops
  from tensorflow.python.ops import state_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.ops import variable_v1
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 6 for calling a global function with example usage: _get_global_step_read(graph) and returns: None, global_step_read_tensors