def loss_count_hash
      @loss_count_hash ||= matches.each_with_object(Hash.new(0)) { |match, hash| hash[get_match_loser(match)] += 1 }
    end
def loss_count_hash
      @loss_count_hash ||= matches.each_with_object(Hash.new(0)) { |match, hash| hash[get_match_loser(match)] += 1 }
    end
Get a hash of the number of losses of each team. Used by tournament systems.

 @return [Hash{team => Number}] a mapping from teams to losses