Subscribing to a topic with Python

edit

Hello people, I've had trouble subsciribing to a topic of type: /robot0/odom

Where odom is a type of nav_msgs/Odometry and it brings me x,y coordinates and orientation.

I've written a simple code for this, but when I run the script, it's not printing anything on the terminal.

#!/usr/bin/env python

import rospy
from nav_msgs.msg import Odometry

def callback(msg):
x=msg.pose.pose.position.x
y=msg.pose.pose.position.y
orientation_z=msg.pose.pose.orientation.z
orientation_w=msg.pose.pose.orientation.w

rospy.loginfo('x: {}, y:{}, orientation_z:{},' .format(x,y, orientation_z))

def main():
    rospy.init_node('ekf_slam')
    rospy.Subscriber("/robot0/odom",Odometry,callback)
    rospy.spin()

if __name__ == '__main__':
    main()

This code was working well when I had to subscribe on a topic with just rospy.Subscriber("/odom",Odometry,callback), but as soon as I switched the program and the topic became /robot0/odom type I began having problems.

Any help would be really appreciated.