code: def head_to_head(self, home_num, away_num):
          
          if home_num in self.home_fo and away_num in self.home_fo[home_num]['opps']:
              h_fo = self.home_fo[home_num]['opps'][away_num]
              a_fo = self.away_fo[away_num]['opps'][home_num]
              return {
                  'home': { k: h_fo[k] for k in self.__zones },
                  'away': { k: a_fo[k] for k in self.__zones }
              }
          else:
              return { }
docs: Return the head-to-head face-off outcomes between two players.
          If the matchup didn't happen, ``{ }`` is returned.
          
          :param home_num: the number of the home team player
          :param away_num: the number of the away team player
          :returns: dict, either ``{ }`` or the following
          
          .. code:: python
          
              {
                  'home/away': {
                      'off/def/neut/all': { 'won': won, 'total': total }
                  }
              }