Boomerang implementing logic

[Piethon]

Are there any problems in using the boomerang. Also, there's a question that's been itching at me. What is pos? Whenever I make a game, I make it representing an x and y value. But the way pos is being interacted with makes it look like it's not made that sort of way. Could you give me an example of what it would look like printed?

I'm not sure if you mean this:

WEAPONS['boomerang'] = {'img': 'boomerang.png',
                       'speed': 340,
                       'lifetime': 550,
                       'rate': 900,
                       'kickback': 0,
                       'spread': 3,
                       'damage': 8,
                       'size': 'boomerang',
                       'count': 1}

This is in the player class, that the player is able to shoot weapons:

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))

The position is a vector. vec is defined as this: vec = pg.math.Vector2

class Boomerang(pg.sprite.Sprite):
    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
        # spread = uniform(-BLOWPIPE_SPREAD, BLOWPIPE_SPREAD)
        self.vel = dir * WEAPONS[game.player.weapon]['speed']
        self.spawn_time = pg.time.get_ticks()
        self.rot = 360
        self.last = pg.time.get_ticks()
        self.cooldown = 300
        self.direction = +1

    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()
        if self.game.player.weapon == 'boomerang':
            now = pg.time.get_ticks()
            if now - self.last >= self.cooldown:
                self.direction = -1
                #self.pos -= self.vel * self.game.dt
            self.pos += self.vel * self.game.dt
            self.rect.center = self.pos

And yes, I can use the boomerang. It flies forward but is not coming back to the player.