code: def TestDeviceFuncPinVariableToCpu(op):
      if op.device:
          return op.device
      return (
          "/cpu:0"
          if op.node_def.op in ["Variable", "VariableV2"]
          else op.device
      )
  
imports: from tensorflow.core.framework import attr_value_pb2
  from tensorflow.core.framework import function_pb2
  from tensorflow.core.framework import graph_pb2
  from tensorflow.core.framework import node_def_pb2
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import function
  from tensorflow.python.framework import graph_util
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_util
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import gen_state_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variable_v1
  from tensorflow.python.platform import test
  from tensorflow.python.util import compat
label_desc: Use image node_id 1 for calling a global function with example usage: TestDeviceFuncPinVariableToCpu(op) and returns: unknown, op