Pygame collision sides trouble

Question

i am currentely making my final project for my exam and i'm making a platform game. Actually i'm stuck at the collisions because as you know in a platform game i need a different reaction for the upper, right and left side. I'd like to make position +10 if it collides on the left of the block or -10 if it's the right side. I tried a code but it only works on the top of the block so that's why i need your help! Could you help me to solve this issue?

import pygame
from pygame.locals import *
pygame.init()

fenetre = pygame.display.set_mode((1024,768))
pygame.display.set_caption("Portal Escape")

class Perso(pygame.sprite.Sprite):
    def __init__(self):
        self.image = pygame.image.load("perso.png").convert_alpha()
        self.position = pygame.Rect((3,660),(100,100))
        self.rect = self.image.get_rect()
        self.doit_monter = False
    def monte(self):
        self.position.y -= 5
    def descend(self):
        self.position.y += 1

perso = Perso()

continuer = 1
while continuer:
    accueil = pygame.image.load("menu.jpg").convert()
    fenetre.blit(accueil, (0,0))
    pygame.display.flip()
    continuer_jeu = 1
    continuer_accueil = 1
    choix = 1

    while continuer_accueil:
        pygame.time.Clock().tick(30) #limite les frames de la boucle
        for event in pygame.event.get():
            if event.type == QUIT: #quitter le jeu
                continuer_accueil = 0
                continuer_jeu = 0
                continuer = 0
            elif event.type == KEYDOWN: #choix du menu
                if event.key == K_F1:
                    choix = 1
                    continuer_accueil = 0
#Boucle du choix
    if choix != 0:
        pygame.time.Clock().tick(30)
        fond = pygame.image.load("fond.jpg").convert()
        fenetre.blit(fond, (0,0))
        fenetre.blit(perso.image, perso.position)
        pygame.display.flip()
        pygame.key.set_repeat(400, 30) 
        new_y = 0
        noir=pygame.draw.rect(fenetre,(0, 0, 0),(200,500,250,300))
        bleu=pygame.draw.rect(fenetre,(0, 0, 255),(500,600,200,200))
        portal=pygame.draw.rect(fenetre,(0, 255, 0),(250,700,50,120))
        sol=pygame.draw.rect(fenetre,(50, 50, 50),(0,757,1024,20))
        bloc = [noir, bleu]
        while continuer:
            for event in pygame.event.get():    #Attente des événements
                if event.type == QUIT:
                    continuer = 0
                if event.type == KEYDOWN:
                    if perso.position.collidelist(bloc) != -1:
                        if perso.position.right == noir.left:
                            perso.position.x -= 10
                            print("collide")
                            perso.position.collidelist(bloc) = -1
                        elif perso.position.left == noir.right:
                            perso.position.x += 10
                            print("collide")
                            perso.position.collidelist(bloc) = -1
                        elif perso.position.bottom == noir.top:
                            perso.position.collidelist(bloc) = -1
                            print("collide")
                    if perso.position.collidelist(bloc) == -1:
                        if event.key == K_DOWN and perso.position.y < 660:
                            perso.position.y += 3
                        if event.key == K_UP:
                            perso.doit_monter = True
                            new_y = perso.position.y - 100
                        if event.key == K_RIGHT and perso.position.x < 920:
                            perso.position.x += 10
                        if event.key == K_LEFT and perso.position.x > 3:
                            perso.position.x -= 10
                        if event.key == K_SPACE:
                            fenetre.blit(pygame.transform.flip(fond, True, False))

            if perso.doit_monter == True:
                if perso.position.y > new_y:
                    perso.monte()
                else:
                    perso.doit_monter = False
            else:
                if perso.position.collidelist(bloc) == -1:
                    if perso.position.y < 660:
                        perso.descend()

            fenetre.blit(fond, (0,0))
            noir=pygame.draw.rect(fenetre,(0, 0, 0),(200,500,250,300))
            bleu=pygame.draw.rect(fenetre,(0, 0, 255),(500,600,200,200))
            portal=pygame.draw.rect(fenetre,(0, 255, 0),(250,700,50,120))
            sol=pygame.draw.rect(fenetre,(50, 50, 50),(0,757,1024,20))
            fenetre.blit(perso.image, perso.position)
            pygame.display.flip()

pygame.quit()