rospy_cb_args.py

#!/usr/bin/env python

import rospy

from std_msgs.msg import Empty


def cb(msg, args):
    a1, a2, a3 = args
    rospy.logwarn('args: %s %d %g' % (a1, a2, a3))


rospy.init_node('cb_args')

s = rospy.Subscriber('/e',Empty,cb,callback_args=['a',1,5.5])

rospy.spin()