Initialize the ddp socket

def _init_socket(self):
        """Initialize the ddp socket"""
        # destroy the connection if it already exists
        if self.ddpsocket:
            self.ddpsocket.remove_all_listeners('received_message')
            self.ddpsocket.remove_all_listeners('closed')
            self.ddpsocket.remove_all_listeners('opened')
            self.ddpsocket.close_connection()
            self.ddpsocket = None

        # create a ddp socket and subscribe to events
        self.ddpsocket = DDPSocket(self.url, self.debug)
        self.ddpsocket.on('received_message', self.received_message)
        self.ddpsocket.on('closed', self.closed)
        self.ddpsocket.on('opened', self.opened)