def _determine_installation_status(self):
        """Determine wether this dependency is installed or not.

        Once a module is loaded into the current Python session, importlib can
        not longer be used to determine the installation status. Restart
        Blender to clear the current Python session.
        """
        assert not self.installation_status
        module_spec = importlib.util.find_spec(self.import_name)
        self.installation_status = module_spec is not None
Determine wether this dependency is installed or not.

        Once a module is loaded into the current Python session, importlib can
        not longer be used to determine the installation status. Restart
        Blender to clear the current Python session.
        
photogrammetry_importer/preferences/dependency.py