human
Solve the following python programming problem given the following code:
def user_passes_test(test_func, login_url = None, redirect_field_name = REDIRECT_FIELD_NAME) : 
    '
    Decorator for views that checks that the user passes the given test,
    redirecting to the log-in page if necessary. The test should be a callable
    that takes the user object and returns True if the user passes.
    ' 
    if (not test_func) : 
        from django.conf import settings 
        login_url = settings.LOGIN_URL 
def decorator(view_func) : 
        def _wrapped_view(request, * args, **kwargs) : 
            if test_func (request.user) : 
                return view_func (request, * args, ** kwargs) 
path = urlquote (request.get_full_path ()) 
            tup = (login_url, redirect_field_name, path) 
            return HttpResponseRedirect (('%s?%s=%s' % tup)) 
return wraps (view_func, assigned = available_attrs (view_func)) (_wrapped_view) 
return decorator 

    
    

    Fix the buggy line: if (not test_func) :
assistant
#Here is Python program to fix the buggy line: if (not test_func) :
.

if (not login_url) :