speed : speed IN speed_unit

def p_speed_conversion(self, p):
        'speed : speed IN speed_unit'
        logger.debug('speed = speed %s in speed unit %s', p[1], p[3])
        information_unit, duration = p[3]
        p[0] = '{0: {1}}'.format(p[1],
                                 '{0}/{1}'.format(information_unit, duration))