code: def _is_known_dtype(dt):
      """Helper returning True if dtype is known."""
      return _is_known_unsigned_by_dtype(
          dt
      ) or _is_known_signed_by_dtype(dt)
  
imports: import functools
  import hashlib
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  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 array_ops_stack
  from tensorflow.python.ops import check_ops
  from tensorflow.python.ops import cond
  from tensorflow.python.ops import control_flow_ops
  from tensorflow.python.ops import linalg_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn
  from tensorflow.python.util import tf_inspect
label_desc: Use image node_id 9 for calling a global function with example usage: _is_known_dtype(dt) and returns: unknown