human
Solve the following python programming problem given the following code:
@ graken ('binary') 
def _arith_expr_(self) : 
    self._term_ () 
    def block0() : 
        with self._group () : 
            with self._choice () : 
                with self._option () : 
                    self._token ('+') 
with self._option () : 
                    self._token ('-') 
self._error ('expecting one of: + -') 
self._term_ () 
self._closure (self) 

    
    

    Fix the buggy line: self._closure (self)
assistant
#Here is Python code to fix the buggy line: self.

self._closure (def block0()