def METHOD_NAME(self):
    tokens = [['a', 'b', 'c', 'd'],
              ['a', 'd', 'e'],
              ['e', 'c']]
    doc_topics = np.array([[0.6, 0.1, 0.3],
                           [0.2, 0.6, 0.2],
                           [0.2, 0.3, 0.5]])
    marg_prob, num_tokens = self.model._marginal_probability(tokens, doc_topics)
    np.testing.assert_allclose(marg_prob, [[0.37777778], [0.31111111], [0.31111111]])
    self.assertEqual(9, num_tokens)