title: ModuleNotFoundError No module named apt_pkg
body: <p>I am trying to add a repo using command </p>
  
  <pre><code> sudo add-apt-repository ppa:gezakovacs/ppa
  </code></pre>
  
  <p>Following is complete error - </p>
  
  <pre><code>    Traceback (most recent call last):
  File "/usr/bin/add-apt-repository", line 11, in &lt;module&gt; from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in &lt;module&gt;
      import apt_pkg
  ModuleNotFoundError: No module named 'apt_pkg'
  Error in sys.excepthook:
  Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes
  File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in &lt;module&gt; from apport.report import Report
  File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in &lt;module&gt;
      import apport.fileutils File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in &lt;module&gt; from apport.packaging_impl 
  import impl as packaging 
  File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 23, in &lt;module&gt;
      import apt
  File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in &lt;module&gt;
      import apt_pkg
  ModuleNotFoundError: No module named 'apt_pkg'
  
  Original exception was:
  Traceback (most recent call last):
  File "/usr/bin/add-apt-repository", line 11, in &lt;module&gt; from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in &lt;module&gt;
      import apt_pkg
  ModuleNotFoundError: No module named 'apt_pkg'
  </code></pre>
  
  <p>getting above error.</p>
  
  <p>I have install python2 , Python3.5 &amp; Python3.6 installed on Xubuntu 16.04.
  Does it causing any issue???</p>