code: def test_mismatched_dtype_error(self):
      ssm1 = self._dummy_model(dtype=self.dtype)
      ssm2 = self._dummy_model(dtype=np.float16)
  
      with self.assertRaisesRegexp(Exception, "dtype"):
          _ = AdditiveStateSpaceModel(component_ssms=[ssm1, ssm2])
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import linear_gaussian_ssm
  from tensorflow_probability.python.distributions import mvn_diag
  from tensorflow_probability.python.internal import tensorshape_util
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.sts.components.local_linear_trend import LocalLinearTrendStateSpaceModel
  from tensorflow_probability.python.sts.components.sum import AdditiveStateSpaceModel
label_desc: Use image node_id 10 for calling the _AdditiveStateSpaceModelTest obj's underlying member method code with example usage: obj.test_mismatched_dtype_error() without return types