def assert_no_eos_at_end(self, x, x_len, eos):
        """Asserts that the last token of each sentence in x is not EOS """
        for i in range(len(x_len)):
            self.assertNotEqual(
                x[x_len[i] - 1][i],
                eos,
                "Expected no eos (token id {eos}) at the end of sentence {i}.".format(
                    eos=eos, i=i
                ),
            )
Asserts that the last token of each sentence in x is not EOS 
decoding/IAD/fairseq/tests/test_noising.py