code: def _OpError(self, x, dtype, err):
      with self.assertRaisesOpError(err):
          self.evaluate(math_ops.cast(x, dtype))
  
imports: import numpy
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_state_ops
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 14 for calling the CastOpTest obj's underlying member method code with example usage: obj._OpError(x, dtype, err) without return types