human
Solve the following python programming problem given the following code:
def _convert_slice(self, s) : 
    def _slice_to_indexes(s) : 
        start = s.start 
        stop = s.stop 
        if (isinstance (start, int) or isinstance (stop, int)) : 
            return (start, stop) 
if start : 
            start = self.database.zrank (self.key, start) 
            if (start is None) : 
                raise KeyError (s.start) 
if stop : 
            stop = self.database.zrank (self.key, stop) 
            if (stop is None) : 
                raise KeyError (s.stop) 
return (start, stop) 
(start, stop) = _slice_to_indexes (s) 
    start = (start or 0) 
    if (not stop) : 
        stop = (- 1) 
else : 
        stop -= 1 
return (start, self) 

    
    

    Fix the buggy line: return (start, self)
assistant
#Here is Python program to fix the buggy line: return (start, self)
.

return (start, stop)