[PyGame] Problem with colorkey

[Windspar]

Converting the image first. Then set colorkey. You don't add colorkey to screen. Also you need to refresh screen.
It also better to use a path tool for joining paths. It makes it more portable.

from pathlib import Path
from sprites import Sprite
import pygame as py
screen = py.display.set_mode((300, 300))
Sprite.load('button_icon', Path('Ressources', 'Sprites', 'button_icon.png'))
sprt = Sprite.get('button_icon', (256, 64), (128, 0, 64, 64))
sprt.convert()
sprt.set_colorkey((sprt.get_at(0, 0))

running = True
while running:
    for event in py.event.get():
        if event.type == py.QUIT:
            running = False
    
    # Refresh screen
    screen.fill('black')
    screen.blit(sprt, (0, 0))
    py.display.flip()