code: def testMatmulError(self):
      with self.assertRaisesRegex(ValueError, r""):
          math_ops.matmul(
              array_ops.ones([], np.int32),
              array_ops.ones([2, 3], np.int32),
          )
      with self.assertRaisesRegex(ValueError, r""):
          math_ops.matmul(
              array_ops.ones([2, 3], np.int32),
              array_ops.ones([], np.int32),
          )
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from six.moves import range
  import tensorflow.compat.v2
  from trax.tf_numpy.numpy_impl import array_ops
  from trax.tf_numpy.numpy_impl import arrays
  from trax.tf_numpy.numpy_impl import math_ops
label_desc: Use image node_id 7 for calling the MathTest obj's underlying member method code with example usage: obj.testMatmulError() without return types