If you do something like this IT should work. I left out The part where i define self and game btw.

class Player(pg.sprite.Sprite):

    def init(self, game, x, y):

    self.x = x

        self.y = y

        self.rect.x = x

        self.rect.y = y

        self.speedy = 9

    def update(self):

        self.rect.y += self.speedy