def def_coordinator(self, year):
        """Returns the coach ID for the team's DC in a given year.

        :year: An int representing the year.
        :returns: A string containing the coach ID of the DC.
        """
        try:
            dc_anchor = self._year_info_pq(year, 'Defensive Coordinator')('a')
            if dc_anchor:
                return dc_anchor.attr['href']
        except ValueError:
            return None