Setpoint position crashes using reference frame

Using "base_link" as ref_frame argument in class SetpointHandler in position function, the node crashes with the following error:

File "/home/patrick/mbzirc_ws/src/mbzirc_ch1/mbzirc_obstacle_task/nodes/statemachine", line 124, in execute userdata.mav.setpoint.position([0, 0, 0], yaw=0.785398163, ref_frame="base_link") #turn 45 degrees on spot File "/home/patrick/mbzirc_ws/src/mbzirc_general/mascor_px4_control/src/mascor_px4_control/setpointhandler.py", line 123, in position tf_pose = self.transform(pose_stamped, self.__ref_frame) File "/home/patrick/mbzirc_ws/src/mbzirc_general/mascor_px4_control/src/mascor_px4_control/setpointhandler.py", line 197, in transform raise TypeException('Type %s if not loaded or supported'% str(key)) TypeException

Using the default None does not crash the node, but that's not what I want the function to do.

Fix this, please!