Can't see my python node in rosnode list?

edit

I am trying to simulate a simple code in Gazebo to takeoff, but there is no response. However, I do not have any error codes and after typing rosnode list I don't see my python node. Could some please explain to me what could be the cause of this?

#!/usr/bin/env python 

#import library ros 
import rospy 
from geometry_msgs.msg import Twist
from std_msgs.msg import Empty

rospy.init_node('my_drone_node',anonymous=True)

empty= Empty()

pub_takeoff = rospy.Publisher('/ardrone/takeoff',Empty,queue_size =10)

land_drone = rospy.Publisher('ardrone/land',Empty,queue_size=10)

pub_takeoff.publish(empty)