Rospy launch multiple file.launch from python node

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Hi everyone.

I would like to know if there are libraries or functions for launch one or more file.launch from a python node without waiting the end of the first node to launch the second. Specifically, my python node will be a simple subscriber that will read the node name to launch from a specific message:

import rospy
from std_msgs.msg import node_name


def node_launch(data):
    node = data.data
    ---------------


def listener():
    rospy.init_node('node_name')
    rospy.Subscriber("chatter", String, node_launch)
    rospy.spin()

I would like to know how to implement the logic to launch a node inside the def node_launch (data): without it waiting for the end of the node and being able to launch another node if required. Are there any procedures or libraries to do this or do I have to create with differents threads?

Thanks everyone.