code: def testFlatten(self):
      a1 = np.array([[[1, 2], [3, 4]], [[5, 6], [7, 8]]])
      a2 = _get_weak_tensor(a1)
      self.assertAllEqual(a1.flatten("C"), a2.flatten("C"))
      self.assertAllEqual(a1.flatten("F"), a2.flatten("F"))
      self.assertAllEqual(a1.flatten("C"), a2.flatten("A"))
      self.assertAllEqual(a1.flatten("C"), a2.flatten("K"))
      with self.assertRaises(ValueError):
          a2.flatten("invalid")
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import flexible_dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.framework import weak_tensor
  from tensorflow.python.ops import weak_tensor_ops
  from tensorflow.python.ops import weak_tensor_test_util
  from tensorflow.python.ops.numpy_ops import np_array_ops
  from tensorflow.python.ops.numpy_ops import np_arrays
  from tensorflow.python.ops.numpy_ops import np_math_ops
  from tensorflow.python.ops.numpy_ops import np_random
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 13 for calling the MathTest obj's underlying member method code with example usage: obj.testFlatten() without return types