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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def vehicle_type_string(self, hb):
        '''return vehicle type string from a heartbeat'''
        if hb.type == mavutil.mavlink.MAV_TYPE_FIXED_WING:
            return 'Plane'
        if hb.type == mavutil.mavlink.MAV_TYPE_GROUND_ROVER:
            return 'Rover'
        if hb.type == mavutil.mavlink.MAV_TYPE_SURFACE_BOAT:
            return 'Boat'
        if hb.type == mavutil.mavlink.MAV_TYPE_SUBMARINE:
            return 'Sub'
        if hb.type in [mavutil.mavlink.MAV_TYPE_QUADROTOR,
                           mavutil.mavlink.MAV_TYPE_COAXIAL,
                           mavutil.mavlink.MAV_TYPE_HEXAROTOR,
                           mavutil.mavlink.MAV_TYPE_OCTOROTOR,
                           mavutil.mavlink.MAV_TYPE_TRICOPTER,
                           mavutil.mavlink.MAV_TYPE_DODECAROTOR]:
            return "Copter"
        if hb.type == mavutil.mavlink.MAV_TYPE_HELICOPTER:
            return "Heli"
        if hb.type == mavutil.mavlink.MAV_TYPE_ANTENNA_TRACKER:
            return "Tracker"
        return "UNKNOWN(%u)" % hb.type