Callback function to receive and save Pose3d. 

        @param odom: ROS Odometry received
        
        @type odom: Odometry

def __callback (self, odom):
        '''
        Callback function to receive and save Pose3d. 

        @param odom: ROS Odometry received
        
        @type odom: Odometry

        '''
        pose = odometry2Pose3D(odom)

        self.lock.acquire()
        self.data = pose
        self.lock.release()