async def eval_issue_1(serialized_citation):
    """
    Return 1 if the `npl_publn_id` is in the `when`field, else None
    See: https://github.com/cverluise/SciCit/issues/1
    :param serialized_citation: dict
    :return: int or None
    """
    if "when" in serialized_citation.keys():
        return (
            1
            if str(serialized_citation["npl_publn_id"]) in serialized_citation["when"]
            else None
        )