问游戏字体属性错误

EN

import sys, pygame as pg, random




class Game:
    def __init__(self):
         #initialize game window, etc
         pg.init()
         pg.font.init()
         pg.mixer.init()
         self.screen = pg.display.set_mode((800, 600))
         pg.display.set_caption('myFirstGame')
         self.running = True
         self.font_name = pg.font.match_font('calibri')


    def new(self):
        #resets the game
        self.score = 0
        self.run()

    def run(self):
        #game loop
        self.playing = True
        while self.playing:
            self.draw()


    def draw(self):
         #game loop draw
         self.screen.fill(0, 0, 0)

         self.all_sprites.draw(self.screen)
         self.draw_text(str(self.score), 22, white, 800 / 2, 20)
         #after drawing everything, flip the display
         pg.display.flip()



    def draw_text(self, text, size, color, x, y):
        font = pg.font.Font(self.font_name, size)
        text_surface = font.render(text, True, color)
        text_rect = text_surface.get_rect()
        text_rect.midtop = (x, y)
        self.screen.blit(text_surface, text_rect)

 g = Game()
 while g.running:
     g.new()
     g.show_go_screen()

 pg.quit()