Traceback (most recent call last):
  File "/usr/local/bin/arandr", line 41, in <module>
    from screenlayout.gui import main
  File "/usr/local/lib/python3.7/site-packages/screenlayout/gui.py",
  line 28, in <module>
    gi.require_version('Gtk', '3.0')
  File "/usr/local/lib/python3.7/site-packages/gi/__init__.py",
  line 130, in require_version
    raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace Gtk not available