code: def testAssertValidSample(self):
      rate1 = np.array([1.0, 3.0, 2.5], dtype=self.dtype)
      rate2 = np.array([2.1, 7.0, 42.5], dtype=self.dtype)
      dist = self._make_skellam(rate1=rate1, rate2=rate2)
      with self.assertRaisesOpError("has non-integer components"):
          self.evaluate(dist.prob([-1.2, 3.0, 4.2]))
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import skellam
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 12 for calling the _SkellamTest obj's underlying member method code with example usage: obj.testAssertValidSample() without return types