[PyGame] how to make objects move at a precise amount of time?

[Zhaleh]

Hi everybody. I'm quite a beginner in programming. I wrote a code that produces an image moving left and right until it hits the walls and change direction. After each collision to the wall, I want it to move at a different speed and this time should be exact in my work. So for my project, I need it to hit the walls 6 times with inter collision times being 500ms, 500ms, 1000ms, 750ms, and 250ms. My code doesn't produce exact times. What should I do to have these precise timings between collisions?
Here is my code:

import pygame 
pygame.init()
screen=pygame.display.set_mode((800,600)) 

pygame.display.set_caption('visual rhythm')
icon=pygame.image.load("song.png")
pygame.display.set_icon(icon)

playerImg=pygame.image.load('spaceship.png')
playerX=370
playerY=400
def player(x,y):
    screen.blit(playerImg,(int(x),int(y)))

acceleration=[0.5, -0.5 , 1 , -0.7 , 0.3]
count=0
count2=0
while count2<len(acceleration):
    screen.fill((0,255,0))
    playerX+=acceleration[count]
    player(playerX,playerY)
    pygame.display.update()
    if playerX>=746 or playerX<1:
        count+=1
        count2+=1