human
Solve the following python programming problem given the following code:
@ mock.patch.object (task.LOG, 'warn') 
def test_update_progress_upper_bound(self, mocked_warn) : 
    result = [] 
    def progress_callback(event_type, details) : 
        result.append (details.pop ('progress')) 
a_task = ProgressTask () 
    a_task.notifier.register (task.EVENT_UPDATE_PROGRESS, self) 
    a_task.execute ([1.0, 1.5, 2.0]) 
    self.assertEqual ([1.0, 1.0, 1.0], result) 
    self.assertEqual (2, mocked_warn.call_count) 

    
    

    Fix the buggy line: a_task.notifier.register (task.EVENT_UPDATE_PROGRESS, self)
assistant
#Here is Python program to fix the buggy line: a_task.

a_task.notifier.register (task.EVENT_UPDATE_PROGRESS, def progress_callback()