code: def testGradientSmall(self):
      self._gradientTest(
          [[[1, 2, 0], [1, 2, 3], [0, 1, 2]]],
          [[[1, 2], [3, 4], [5, 6]]],
          dtype=dtypes.float64,
      )
  
imports: import itertools
  import numpy
  from tensorflow.python.client import session
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import array_ops_stack
  from tensorflow.python.ops import control_flow_ops
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.ops import linalg_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.ops.linalg import linalg_impl
  from tensorflow.python.platform import benchmark
  from tensorflow.python.platform import test
label_desc: Use image node_id 9 for calling the TridiagonalMulOpTest obj's underlying member method code with example usage: obj.testGradientSmall() without return types