human
Solve the following python programming problem given the following code:
def _binary_infix_op(infix_sym) : 
    def formatter(translator, expr) : 
        op = expr.op () 
        (left, right) = op.args 
        left_arg = translator.translate (left) 
        right_arg = translator.translate (right) 
        if _needs_parens (left) : 
            left_arg = _parenthesize (left_arg) 
if _needs_parens (right) : 
            right_arg = _parenthesize (right_arg) 
return '{0!s} {1!s} {2!s}'.format (left_arg, infix_sym, right_arg) 
return infix_sym 

    
    

    Fix the buggy line: return infix_sym
assistant
#Here is Python code to fix the buggy line: return infix_sym
.

return def formatter(