Pygame, problem with class collision. please fix?

Question

I want to build Geometry Dash sort of game, but i'm stuck on this element where the enemy collide with a character. I've done both enemy and character as classes and so apparently x.colliderect() doesn't work. Any idea how I could implement this featuer in my code?

DISPLAYING THE WINDOW

#DISPLAY WINDOW
def draw_window(square, triangle, score):
    #SCREEEN
    WIN.fill(black)
    #SCORE
    score_text = FONT.render("Score: " +str(score), 1, white)
    WIN.blit(score_text, (width - score_text.get_width() - 10, 10))
    #OBJECTS
     #LINE
    pygame.draw.line(WIN, blue, (0, 400), (900, 400), 10)
     #SQUARE
    square.draw()
     #TRIANGLE
    triangle.draw()

    pygame.display.update()

TRIANGLE (ENEMY) CLASS

#TRIANGLE
class Triangle():
    def __init__(self):
        self.x = 700
        self.vel = 10

    def draw(self):
        pygame.draw.polygon(WIN, green, [[self.x, 395], [self.x + 50, 395][self.x + 25, 345]])

def move(self, score):
    self.x -= 5
    if self.x == -50:
        self.x = 900
        score += 1
        print(score)

    return score

SQUARE (CHARACTER) CLASS

#SQUARE
class Square():
    def __init__(self):
        self.y = 295
        self.vel = 10

    def draw(self):
        pygame.draw.rect(WIN, red, pygame.Rect(50, self.y, 100, 100))

    def jump(self, jumpCount):
        jump = True
        if jumpCount >= -10:
            neg = 1
            if jumpCount < 0:
                neg = -1
            self.y -= (jumpCount ** 2) * 0.5 * neg
            jumpCount -= 0.5
        else:
            jump = False
            jumpCount = 10

        return jump, jumpCount

MAIN GAME LOOP

def main():
    score = 0
    jump = False
    jumpCount = 10
    triangle = Triangle()
    square = Square()

    run = True
    while run:
        clock.tick(FPS)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False

            #JUMPING
            if event.type == pygame.KEYDOWN:
                if not jump and event.key == pygame.K_SPACE:
                    jump = True

            if event.type == square_hit:
                pass #HERE IS THE COLLISION PROBLEM

        if jump:
            jump, jumpCount = square.jump(jumpCount)

        draw_window(square, triangle, score)
        score = triangle.move(score)

    pygame.quit()

if __name__ == "__main__":
    main()