in Python / Django I can not reassign a variable, the script is ignored

I'm doing a Login with Python / Django / MongoDB this is my function

from django.shortcuts import render
from pymongo import MongoClient
import bcrypt


def login( req ):
    #hashed = bcrypt.hashpw( p.encode('utf8'), bcrypt.gensalt() )
    response = { 'error': 'Ni siquiera llegué' }

    if req.POST['username'] and req.POST['password']:
        u = req.POST['username']
        p = req.POST['password']
        client = MongoClient()
        result = client['db']['users'].find({'nombre': u})

        if result:
            for res in result:
                if bcrypt.checkpw( p, res['password'] ):
                    response = { 'error': 'Contraseña buena papus!' }
                else:
                    response = { 'error': 'Contraseña inválida' }
                break   
        else:
            response = { 'error': 'No hay alguien con ese nombre' }
    else:
        response = { 'error': 'Usuario o contraseña vacío' }


    return render( req, 'crawler/login.html', response )

When the variable returns to the login, it always appears 'I did not even arrive' in the error sent, as if it were ignoring all the IFs, I do not understand what is happening