Boomerang implementing logic

[Piethon]

Hello everybody.

I am making a game with pygame and till know there are different weapons such as a shurikan and a blowpipe.
But now I wanted to implement a boomerang, and I don't know what to do, that it comes back to the player, after a certain amount of time.

So in a settings file, I am defining my weapons (I'm posting the code of the shurikan, because I haven't implemented a boomerang yet. I first want to know how to make it coming back to the player):

WEAPONS['shurikan'] = {'speed': 575,
                       'lifetime': 800,
                       'rate': 400,
                       'kickback': 0,
                       'spread': 3,
                       'damage': 8,
                       'size': 'shurikan',
                       'count': 1}

Then we have the shoot section:

class Player(pg.sprite.Sprite):
    def __init__(self, game, x, y):
        # I've left out the things that are not important for this question 
        self.weapon = 'shurikan'
        self.shurikan = True
        self.shoot_ammo = True

    # Then there is key press stuff and now the shoot section

     def shoot(self):
        if self.shoot_ammo == True:
            now = pg.time.get_ticks()
            if now - self.last_shot > WEAPONS[self.weapon]['rate']:
                self.last_shot = now
                dir = vec(1, 0).rotate(-self.rot)
                pos = self.pos + BARREL_OFFSET.rotate(-self.rot)
                self.vel = vec(-WEAPONS[self.weapon]['rate'], 0).rotate(-self.rot)
                for i in range(WEAPONS[self.weapon]['count']):
                    spread = uniform(-WEAPONS[self.weapon]['spread'], WEAPONS[self.weapon]['spread'])
                    Blowpipe(self.game, pos, dir.rotate(spread))

Then there is also a weapon class.

class Blowpipe(pg.sprite.Sprite): # I haven't renamed the class yet but it is for all kind of weapons
    def __init__(self, game, pos, dir):
        self.groups = game.all_sprites, game.blowpipes
        pg.sprite.Sprite.__init__(self, self.groups)
        self.game = game
        self.image = game.blowpipe_images[WEAPONS[game.player.weapon]['size']]
        self.rect = self.image.get_rect()
        self.pos = vec(pos)
        self.rect.center = pos
        self.vel = dir * WEAPONS[game.player.weapon]['speed']
        self.spawn_time = pg.time.get_ticks()
        self.rot = 360

    def update(self):
        self.pos += self.vel * self.game.dt
        self.rect.center = self.pos
        if pg.sprite.spritecollideany(self, self.game.walls):
            self.kill()
        if pg.time.get_ticks() - self.spawn_time > WEAPONS[self.game.player.weapon]['lifetime']:
            self.kill()

So I just posted some code here, because I want to know, how to make the boomerang coming back to the player and how to implement that in my code.

Hope it is not so complicated for you to understand.

Thanks for helping me.

Piethon