问题 When I try: sudo add-apt-repository ppa:kirillshkrogalev/ffmpeg-next in Ubuntu, the terminal show this error message: Traceback (most recent call last): File "/usr/bin/add-apt-repository", line 11, in <module> from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in <module> import apt_pkg ImportError: No module named 'apt_pkg' I have two version of python, one is 2.7 the