def load_pip_requirements(self, files_map=None, freeze=True):
        if files_map is None:
            files_map = self.default_pip_files
        for group, requirements_txt in files_map.items():
            path = Path(requirements_txt)
            if not path.exists() and group.lower() == "all" and freeze:
                cmd = envoy.run("pip freeze")
                self[group].loads(cmd.std_out)
            elif path.exists():
                self[group].load(path)
def refresh(self):
        """refreshes the Gtk.Liststore"""
        self.backendid_to_iter = {}
        self.liststore.clear()

        # Sort backends
        # 1, put default backend on top
        # 2, sort backends by human name
        backends = list(self.req.get_all_backends(disabled=True))
        backends = sorted(backends,
                          key=lambda backend: (not backend.is_default(),
                                               backend.get_human_name()))

        for backend in backends:
            self.add_backend(backend)
            self.on_backend_state_changed(None, backend.get_id())