human
Solve the following python programming problem given the following code:
def test_deny_decorator(self) : 
    '
        Ensures @xframe_options_deny properly sets the X-Frame-Options header.
        ' 
    @ xframe_options_deny 
    def a_view(request) : 
        return HttpResponse () 
r = a_view (HttpRequest ()) 
    self.assertEqual (self ['X-Frame-Options'], 'DENY') 

    
    

    Fix the buggy line: self.assertEqual (self ['X-Frame-Options'], 'DENY')
assistant
#Here is Python code to fix the buggy line: self.

self.assertEqual (r ['X-Frame-Options'], 'DENY')