class Team(Base):
  __tablename__ = 'teams'
  id =Column(Integer, primary_key=True)
  name = Column(String)
  def  __init__(self, name):
    self.name = name
  def get_team(self, name):
    q = sess.query(Team).filter(Team.name == name)
    try:
      x = q.first()
      return x
    except:
      t = Team(name)
      sess.add(t)
      return t
class Game(Base):
  __tablename__ = 'games'
  id =Column(Integer, primary_key=True)
  date = Column(DateTime)
  home_id = Column(Integer, ForeignKey('teams.id'))
  visitor_id = Column(Integer, ForeignKey('teams.id'))
  home = relationship(Team, backref=backref('home'))
  visitor = relationship(Team, backref=backref('visitor'))
  def __init__(self, date, home, away):

    self.date = date
    self.home = Team.get_team(home)
    self.visitor = Team.get_team(away)