avoid intersection of multiple enemies(sprite) in pygame

Question

I am new to pygame and trying to make space invaders. So when I spawn enemies the enemies usually overlap each other which I don't want, I tried to fix it for hours but nothing worked and ended up here. I want the enemies not to intersect each other (here's a picture of what's happening. I don't want the results like the enemies in blue. I want the results like in red.)

code

class Enemy(pygame.sprite.Sprite):
    hp = 100
    X_change = 3
    Y_change = 40
    def __init__(self):
        super().__init__()
        self.image = pygame.image.load("images/enemy.png")
        self.X = random.randint(0, 800)
        self.Y =  random.randint(33,130)
        self.rect = self.image.get_rect(center = (self.X, self.Y))
    def update(self):
        # movement
        self.rect.x += self.X_change
        if self.rect.x <= 0:
            self.X_change = 3
            self.rect.y += self.Y_change
        elif self.rect.x>= 736:
            self.X_change = -3
            self.rect.y += self.Y_change