multiprocessing: rospy.init_node() has already been called

edit

I have a python script which initializes a node through rospy.init_node() and in a later line it does the following:

robot2 = multiprocessing.Process(target=robot, kwargs={'robot_ip': ip2, 'uri': uri})
robot2.start()

which involves starting a new roscore with a new uri, changing the environmental variable by os.environ["ROS_MASTER_URI"] = "http://localhost:" + uri and initializing a new node with rospy.init_node(). However, for the second node the it gives the error that rospy.init_node() is already called.

My expectation however is that since the second node is made after in a seperate process, with separate roscore, and separate environmental variable, this error should not come.

An example similar to my code is the following:

class TheRobot(object):
    def __init__(self,
                 robot_ip='172.16.1.2',
                 **kwargs):

        self.uri  = str(uri)
        os.environ["ROS_MASTER_URI"] = "http://localhost:" + self.uri
        venv = os.environ.copy()
        self.roscore_proc = subprocess.Popen(["roscore", '-p', self.uri],
                                             stdout=None,  
                                             stderr=sys.stderr,
                                             preexec_fn=os.setsid
                                             )
        rospy.init_node('robot_setup_node_{}'.format(self.uri))




class DoubleRobot(TheRobot):
    def __init__(self, 
                 ip1='172.16.0.2',
                 ip2='172.16.1.2',
                 uri=None,
                 **kwargs):

        super().__init__(robot_ip=ip1, uri=uri)
        robot2 = multiprocessing.Process(target=TheRobot, kwargs={'robot_ip': ip2, 'uri': uri+1})
        robot2.start()


twin_panda = DoubleRobot(ip1='172.16.0.2', ip2='172.16.1.2', uri=11314)

a similar question but without multiprocessing can be found here but it did not help. In general,I'd be grateful for any suggestion for the above purpose, or for any other alternative.