def check_and_return_expected(value, undefined_value, expected_value, name=None):
    """
    Return the expected value while checking if the given value is undefined or
    equal to the expected value.
    """
    if (undefined_value is None and value is None) or (undefined_value == value):
        return expected_value
    if value != expected_value:
        str_name = "" if name is None else "{} ".format(name)
        str_value = "{}" if name is None else "({})"
        str_value = str_value.format(value)
        raise ValueError(
            "Expected {}{} == {}".format(str_name, str_value, expected_value)
        )
    return expected_value
Return the expected value while checking if the given value is undefined or
equal to the expected value.
fairseq/models/speech_to_text/utils.py