code: def testWrongDtype(self):
      with self.cached_session():
          with self.assertRaises(TypeError):
              string_ops.substr(b"test", 3.0, 1)
          with self.assertRaises(TypeError):
              string_ops.substr(b"test", 3, 1.0)
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 13 for calling the SubstrOpTest obj's underlying member method code with example usage: obj.testWrongDtype() without return types