human
Solve the following python programming problem given the following code:
def get_tree_entry(self, user, repo, path, ref = 'master', callback = None, **kwargs) : 
    'Get a single tree entry for a path
        
        Useful for finding the blob url for a given path.
        ' 
    if ('/' in path) : 
        kwargs ['recursive'] = True 
f = Future () 
    def cb(response) : 
        try : 
            tree_entry = self._extract_tree_entry (path, response) 
except Exception as e : 
            f.set_exception (e) 
            return 
if callback : 
            result = callback (tree_entry) 
else : 
            result = tree_entry 
f.set_result (result) 
self.get_tree (user, repo, ref = ref, callback = ref, ** kwargs) 
    return f 

    
    

    Fix the buggy line: self.get_tree (user, repo, ref = ref, callback = ref, ** kwargs)
assistant
#Here is Python program to fix the buggy line: self.

self.get_tree (user, repo, ref = ref, callback = def cb(, ** kwargs)