Python Coin Collecting Game 1.0

#Code by Umut Bilgic, Ankara, Turkey.
#Public release: 11/16/2013
#Release version: 1.0 - no coins yet
from pygame.locals import *
import pygame
import sys
import time

image_resources = "C:/Users/user/Desktop/Pygame App/app_resources/image_resources/"
sound_resources = "C:/Users/user/Desktop/Pygame App/app_resources/sound_resources/"

width,height = 400,400
size = (width,height)

def quit_game():
    pygame.quit()
    sys.exit("System exit.")

class GetSource:
    def background(self,image):
        return pygame.image.load(image_resources + image).convert()
    def player(self,image):
        return pygame.image.load(image_resources + image).convert_alpha()

class Wall(pygame.sprite.Sprite):
    def __init__(self,color,x,y,width,height):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((width,height))
        self.image.fill(pygame.color.Color(color))
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y

class Player(pygame.sprite.Sprite):
    def __init__(self,image):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load(image_resources + image).convert_alpha()
        self.rect = self.image.get_rect()

class Coin(pygame.sprite.Sprite):
    def __init__(self,image):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load(image_resources + image).convert_alpha()
        self.rect = self.image.get_rect()

pygame.init()

screen = pygame.display.set_mode(size)
pygame.display.set_caption("PyGame App")
background = GetSource().background("bg_solid_black_square.jpg")
player = GetSource().player("ball_blue.png")
player_dimension = player.get_width()

x,y = width/2-player_dimension,height/2-player_dimension
movex,movey = 0,0

walls = pygame.sprite.Group()
players = pygame.sprite.Group()
all_sprites = pygame.sprite.Group()

wall_1 = Wall("white", 0, 0, width, 5)
wall_2 = Wall("white", 0, 0, 5, height)
wall_3 = Wall("white", 0, height-5, width, 5)
wall_4 = Wall("white", width-5, 0, 5, height)
player = Player("ball_blue.png")

walls.add(wall_1,wall_2,wall_3,wall_4)
players.add(player)
all_sprites.add(wall_1,wall_2,wall_3,wall_4,player)

while True:

    time.sleep(0.009)

    collide_list_1 = pygame.sprite.spritecollideany(wall_1,players)
    collide_list_2 = pygame.sprite.spritecollideany(wall_2,players)
    collide_list_3 = pygame.sprite.spritecollideany(wall_3,players)
    collide_list_4 = pygame.sprite.spritecollideany(wall_4,players)

    for event in pygame.event.get():
        if event.type == QUIT:
            quit_game()
        if event.type == KEYDOWN:
            if event.key == K_q:
                quit_game()
            elif event.key == K_a:
                movex = -1
            elif event.key == K_d:
                movex = 1
            elif event.key == K_w:
                movey = -1
            elif event.key == K_s:
                movey = 1

        if event.type == KEYUP:
            if event.key == K_a or event.key == K_d:
                movex = 0
            if event.key == K_w or event.key == K_s:
                movey = 0

    if collide_list_1 != None:
        movey = 0
        y += 1
    if collide_list_2 != None:
        movex = 0
        x += 1
    if collide_list_3 != None:
        movey = 0
        y -= 1
    if collide_list_4 != None:
        movex = 0
        x -= 1
    else:
        x += movex
        y += movey

    player.rect.x = x
    player.rect.y = y

    screen.blit(background, (0,0))
    all_sprites.draw(screen)
    all_sprites.update()

    pygame.display.update()