ImportError: dynamic module does not define module export function (PyInit__tf2)

[Ma29-HIT]

Hi there, I'm installing crazyswarm under Ubuntu 18. I have also installed python3.9 on my computer. When doing the final test part, it failed with the following information:

=================================== FAILURES ===================================
_______________________________ test_ros_import ________________________________

@pytest.mark.ros
def test_ros_import():

  from pycrazyswarm.crazyflie import TimeHelper, CrazyflieServer

test_ros.py:6:

---

pycrazyswarm/crazyflie.py:12: in
import tf_conversions
/opt/ros/melodic/lib/python2.7/dist-packages/tf_conversions/init.py:30: in
from .posemath import *
/opt/ros/melodic/lib/python2.7/dist-packages/tf_conversions/posemath.py:29: in
from tf import transformations
/opt/ros/melodic/lib/python2.7/dist-packages/tf/init.py:29: in
from tf2_ros import TransformException as Exception, ConnectivityException, LookupException, ExtrapolationException
/opt/ros/melodic/lib/python2.7/dist-packages/tf2_ros/init.py:38: in
from tf2_py import *

---

from __future__ import absolute_import

from ._tf2 import *
E ImportError: dynamic module does not define module export function (PyInit__tf2)

/opt/ros/melodic/lib/python2.7/dist-packages/tf2_py/init.py:38: ImportError
=========================== short test summary info ============================
FAILED test_ros.py::test_ros_import - ImportError: dynamic module does not de...
=================== 1 failed, 29 passed, 1 skipped in 8.82s ====================

Anyone can help me? I've tried some methods searched online but none of them works.