code: def test_float64(self):
      self._test_grad_accuracy(np.float64, self._grid, self._error64)
      self._test_grad_finite(np.float64)
  
imports: import collections
  import importlib
  import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradient_checker
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops.distributions import special_math
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 6 for calling the NdtrGradientTest obj's underlying member method code with example usage: obj.test_float64() without return types