I need to use virtualenv for nmea_navsat_driver to deal with tf2 problem [closed]

edit

straight dump of the error

(robot) gordonlin@gordonlin-jetson:~$ rosrun nmea_navsat_driver nmea_topic_serial_reader _port:=/dev/ttyACM0 _baud:=9600
Traceback (most recent call last):
  File "/home/gordonlin/robot/src/nmea_navsat_driver-master/scripts/nmea_topic_serial_reader", line 35, in <module>
    import libnmea_navsat_driver.nodes.nmea_topic_serial_reader
  File "/home/gordonlin/robot/src/nmea_navsat_driver-master/src/libnmea_navsat_driver/nodes/nmea_topic_serial_reader.py", line 40, in <module>
    from libnmea_navsat_driver.driver import RosNMEADriver
  File "/home/gordonlin/robot/src/nmea_navsat_driver-master/src/libnmea_navsat_driver/driver.py", line 43, in <module>
    from tf.transformations import quaternion_from_euler
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf/__init__.py", line 30, in <module>
    from tf2_ros import TransformException as Exception, ConnectivityException, LookupException, ExtrapolationException
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf2_ros/__init__.py", line 38, in <module>
    from tf2_py import *
  File "/opt/ros/melodic/lib/python2.7/dist-packages/tf2_py/__init__.py", line 38, in <module>
    from ._tf2 import *
ImportError: dynamic module does not define module export function (PyInit__tf2)

so I want to test whether virtualenv is correct establish ,so i set up the env 3.6. I have two python version 2.7 and 3.6. and the following response

gordonlin@gordonlin-jetson:~$ source env3.6/bin/activate
(env3.6) gordonlin@gordonlin-jetson:~$ cd env3.6
(env3.6) gordonlin@gordonlin-jetson:~/env3.6$ python
Python 2.7.17 (default, Feb 27 2021, 15:10:58) 
[GCC 7.5.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.

but the python version is still default python version 2.7.