input: Write a python function to calculate the average age and highest scorer of a football team.
  ```python
  class Player:
      def __init__(self, name, age, score):
          self.name = name
          self.age = age
          self.score = score
  
  team = FootballTeam()
  team.add_player(Player("John", 25, 10))
  team.add_player(Player("Mike", 30, 15))
  team.add_player(Player("Alex", 22, 20))
  
  assert team.average_age() == 25.666666666666668
  assert team.highest_scorer().name == "Alex"
  assert team.highest_scorer().score == 20
output: class FootballTeam:
      def __init__(self):
          self.players = []
  
      def add_player(self, player):
          self.players.append(player)
  
      def average_age(self):
          total_age = sum(player.age for player in self.players)
          return total_age / len(self.players)
  
      def highest_scorer(self):
          return max(self.players, key=lambda player: player.score)