def p_arithmetic_expression(self, p):
        '''
        expression : expression PLUS  expression
                   | expression MINUS expression
                   | expression TIMES expression
                   | expression DIV   expression
                   | expression MOD   expression
        '''
        p[0] = BinaryOperationNode(left=p[1],
                                   operator=p[2],
                                   right=p[3])
expression : expression PLUS  expression
                   | expression MINUS expression
                   | expression TIMES expression
                   | expression DIV   expression
                   | expression MOD   expression