code: def _is_none_or_undef(value):
      """Tests whether a value is None or undefined.
  
      AutoGraph represents undefined symbols using special objects of type Undefined
      or UndefinedReturnValue.
  
      Args:
        value: value to test
  
      Returns:
        Boolean
      """
      return (
          (value is None)
          or isinstance(value, variables.UndefinedReturnValue)
          or isinstance(value, variables.Undefined)
      )
  
imports: import functools
  import sys
  import traceback
  import numpy
  from tensorflow.python.autograph.operators import py_builtins
  from tensorflow.python.autograph.operators import variables
  from tensorflow.python.autograph.utils import ag_logging
  from tensorflow.python.autograph.utils import misc
  from tensorflow.python.autograph.utils import tensors
  from tensorflow.python.autograph.utils import type_registry
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import func_graph
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_conversion
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import tensor_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import cond
  from tensorflow.python.ops import control_flow_assert
  from tensorflow.python.ops import control_flow_util
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import tensor_array_ops
  from tensorflow.python.ops import while_loop
  from tensorflow.python.types import distribute
  from tensorflow.python.util import nest
  from tensorflow.python.util import variable_utils
label_desc: Use image node_id 1 for calling a global function with example usage: _is_none_or_undef(value) and returns: unknown