在類內使用return時的語法錯誤

Question

任何人都可以解釋爲什麼我在has_happened()方法中得到return語句的語法錯誤。

from sys import argv 
import time 
from datetime import date 


class Game(object): 

    def __init__(self, home, away, home_odds, away_odds, date): 
     self.home = home 
     self.away = away 
     self.home_odds_str = home_odds 
     self.away_odds_str = away_odds 
     self.date = date 

    def to_string(self): 
     return self.home + ", " + self.away + ", " + self.home_odds + ", " + self.away_odds + ", " + self.result + ", " + self.date 

    def has_happened(self): 
     dates_split = self.date.split("/") 
     today = date.today() 
     game_date = date(int(dates_split[2]), int(dates_split[1]), int(dates_split[0]) 
     return str(game_date < today) 


game1 = Game("t1", "t2", "7/8", "9/1", "29/9/2016") 
game1.has_happened() 

Answer 1

def has_happened(self): 
    dates_split = self.date.split("/") 
    today = date.today() 
    game_date = date(int(dates_split[2]), int(dates_split[1]), int(dates_split[0])) 
    return str(game_date < today)