@staticmethod
def metadata_updated_on(item):
    """Extracts and coverts the update time from a Meetup item.

        The timestamp is extracted from 'updated' field and converted
        to a UNIX timestamp.

        :param item: item generated by the backend

        :returns: a UNIX timestamp
        """
    ts = item['updated']
    ts = ts / 1000.0
    return ts
