'QueryDict' object is not callable - Python

def new_user_registration (request):
    errors = []
    if 'user' and 'pass' and 'email' and 'pass2' in request.GET:
        pass1 = request.GET('pass')
        pass2 = request.GET('pass2')
        if User.objects.filter (username = request.GET['user']):
            errors.append ('this username already in use')
            return render_to_response ('bc/registration_page.html', locals())
        elif pass1 != pass2:
            errors.append ('You\'r passwords do not match')
        else: 
            new_user = User.objects.create_user (username = request.GET['user'],
                                        password = request.GET['pass'], 
                                        email = request.GET['email'])
            new_user.save()
        return HttpResponseRedirect ('/bc/registration/complete/',locals ())
    else:
        return render_to_response ('bc/registration_page.html/', locals())