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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 wp_draw_callback(self, points):
        '''callback from drawing waypoints'''
        if len(points) < 3:
            return
        from MAVProxy.modules.lib import mp_util
        home = self.wploader.wp(0)
        self.wploader.clear()
        self.wploader.target_system = self.target_system
        self.wploader.target_component = self.target_component
        self.wploader.add(home)
        if self.get_default_frame() == mavutil.mavlink.MAV_FRAME_GLOBAL_TERRAIN_ALT:
            use_terrain = True
        else:
            use_terrain = False
        for p in points:
            self.wploader.add_latlonalt(p[0], p[1], self.settings.wpalt, terrain_alt=use_terrain)
        self.send_all_waypoints()