docs: def setup_installation():
      """Install necessary GUI resources
      
      By default, RAFCON should be installed via `setup.py` (`pip install rafcon`). Thereby, all resources are being 
      installed. However, if this is not the case, one can set the `RAFCON_CHECK_INSTALLATION` env variable to `True`. 
      Then, the installation will be performed before starting the GUI. 
      """
      if os.environ.get("RAFCON_CHECK_INSTALLATION", False) == "True":
          rafcon_root = os.path.dirname(rafcon.__file__)
          installation.assets_folder = os.path.join(rafcon_root, 'gui', 'assets')
          installation.share_folder = os.path.join(os.path.dirname(os.path.dirname(rafcon_root)), 'share')
          installation.install_fonts(logger, restart=True)
          installation.install_gtk_source_view_styles(logger)
          installation.install_libraries(logger, overwrite=False)