How to overwrite the y position of the bird in the game?

Question

Whenever my bird collides with a base then it will jump and his y position will be the y position of the base.

Basically i am stuck at the point whenever the bird jumps from the bottom and while jumping it touches a base it comes down to the starting position of the jump however if it collides with any base in the jump it should take the y coordinate of the bird equal to the y coordinate of that base.

import pygame, sys
from random import randint
pygame.init()

screen = pygame.display.set_mode((350,675))
pygame.display.set_caption("First Game")

x_poss = randint(0,350)
y_poss = randint(0,675)
width = 20
height = 20
vel = 8

bases = []

red = (255,0,0)

image_1 = pygame.image.load('bird.png').convert_alpha()
image_2 = pygame.image.load('base.png').convert_alpha()
image_3 = pygame.image.load('base2.png').convert_alpha()
image_4 = pygame.image.load('enemy.png').convert_alpha()

isJump = False
jumpCount = 10
run = True
base_1 = pygame.draw.rect(screen, (255,255,255), (randint(0,330), randint(0,675), width, height))
base_2 = pygame.draw.rect(screen, (255,255,255), (randint(0,330), randint(0,675), width, height))

def draw_rect(color, x, y, width, height):
    pygame.draw.rect(screen, color, (x,y,width, height))

while len(bases) < 10:
    rect = pygame.Rect(randint(0,330), randint(0,675), width, height)
    if rect.collidelist(bases) < 0:
        bases.append(rect)


while run:
    pygame.time.delay(50)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    key = pygame.key.get_pressed()

    if key[pygame.K_LEFT] and x_poss > vel - width:
        x_poss -= vel

    if key[pygame.K_q]:
        run = False
        sys.exit()

    if key[pygame.K_RIGHT] and x_poss < 350 - vel - width:
        x_poss += vel

    if not(isJump):
        if key[pygame.K_UP] and y_poss > vel:
            y_poss -= vel

        if key[pygame.K_DOWN] and y_poss < 670 - height - vel:
            y_poss += vel

        if key[pygame.K_SPACE]:
            isJump = True
    else:
        if jumpCount >= -10:
            y_poss -= (jumpCount * abs(jumpCount)) * 0.5
            jumpCount -= 1
        else:
            jumpCount = 10
            isJump = False

    bird = pygame.draw.rect(screen, (255,255,255), (x_poss, y_poss, width, height))

    def jump():
        global jumpCount, y_poss
        for base in bases:
            if bird.colliderect(base):
                isJump = True
                if jumpCount >= -10:
                    y_poss -= (jumpCount * abs(jumpCount)) * 0.5
                    jumpCount -= 1
                    
                else:
                    jumpCount = 10
                    isJump = False

    screen.fill((255,255,255))

    draw_rect((255,255,255),x_poss, y_poss, width, height)
    screen.blit(image_1, pygame.draw.rect(screen, (255,255,255), (x_poss, y_poss, width, height)))


    for base_1 in bases[:5]:
        screen.blit(image_2, base_1)
    for base_2 in bases[5:]:
        screen.blit(image_3, base_2)

    for i, base_1 in enumerate(bases):
        if base_1.collidelist(bases[i+1:]) >= 0:
            bases.remove(base_1)
            bases.append(pygame.draw.rect(screen, (255,255,255), (randint(0,330), randint(0,675), width, height)))

    for i, base_2 in enumerate(bases):
        if base_2.collidelist(bases[i+1:]) >= 0:
            bases.remove(base_2)
            bases.append(pygame.draw.rect(screen, (255,255,255), (randint(0,330), randint(0,675), width, height)))


    jump()

    for base in bases:
        base.y += 0

    draw_rect((0,0,0),300, 440, 10, 10)
    screen.blit(image_4, pygame.draw.rect(screen, (0,0,0), (300,440,10,10)))

    pygame.display.update()

pygame.quit()

I think the adjustments should be in this piece of code:

 def jump():
        global jumpCount, y_poss
        for base in bases:
            if bird.colliderect(base):
                isJump = True
                if jumpCount >= -10:
                    y_poss -= (jumpCount * abs(jumpCount)) * 0.5
                    jumpCount -= 1
                    
                else:
                    jumpCount = 10
                    isJump = False