human
Solve the following python programming problem given the following code:
@ mock.patch.object (image_cache, '_fetch', autospec = True) 
def test__download_image(self, mock_fetch) : 
    def _fake_fetch(ctx, uuid, tmp_path, * args) : 
        self.assertEqual (self.uuid, uuid) 
        self.assertNotEqual (self.dest_path, tmp_path) 
        self.assertNotEqual (os.path.dirname (tmp_path), self.master_dir) 
        with open (tmp_path, 'w') as fp : 
            fp.write ('TEST') 
mock_fetch.side_effect = _fake_fetch 
    self.cache._download_image (self.uuid, self.master_path, self.dest_path) 
    self.assertTrue (os.path.isfile (self.dest_path)) 
    self.assertTrue (os.path.isfile (mock_fetch.master_path)) 
    self.assertEqual (os.stat (self.dest_path).st_ino, os.stat (self.master_path).st_ino) 
    with open (self.dest_path) as fp : 
        self.assertEqual ('TEST', fp.read ()) 

    
    

    Fix the buggy line: self.assertTrue (os.path.isfile (mock_fetch.master_path))
assistant
#Here is Python code to fix the buggy line: self.

self.assertTrue (os.path.isfile (self.master_path))