code: def _is_undefined_dimension(d):
      return isinstance(d, tensor_shape.Dimension) and d.value is None
  
file_path: tensorflow/tensorflow/python/ops/tensor_getitem_override.py
imports: import numbers
  import numpy
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.ops import gen_math_ops
  from tensorflow.python.util import dispatch
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 1 for calling a global function with example usage: _is_undefined_dimension(d) and returns: unknown