Get the list of applications that should be backed up by Mackup.

        It's the list of allowed apps minus the list of ignored apps.

        Returns:
            (set) List of application names to back up

def get_apps_to_backup(self):
        """
        Get the list of applications that should be backed up by Mackup.

        It's the list of allowed apps minus the list of ignored apps.

        Returns:
            (set) List of application names to back up
        """
        # Instantiate the app db
        app_db = appsdb.ApplicationsDatabase()

        # If a list of apps to sync is specify, we only allow those
        # Or we allow every supported app by default
        apps_to_backup = self._config.apps_to_sync or app_db.get_app_names()

        # Remove the specified apps to ignore
        for app_name in self._config.apps_to_ignore:
            apps_to_backup.discard(app_name)

        return apps_to_backup