"""Refresh file paths from dag dir if we haven't done it for too long."""
        now = timezone.utcnow()
        elapsed_time_since_refresh = (now - self.last_dag_dir_refresh_time).total_seconds()
        if elapsed_time_since_refresh > self.dag_dir_list_interval:
            
            self.log.info("Searching for files in %s", self._dag_directory)
            self._file_paths = list_py_file_paths(self._dag_directory)
            self.last_dag_dir_refresh_time = now
            self.log.info("There are %s files in %s", len(self._file_paths), self._dag_directory)
            self.set_file_paths(self._file_paths)
            try:
                self.log.debug("Removing old import errors")
                DagFileProcessorManager.clear_nonexistent_import_errors(file_paths=self._file_paths)
            except Exception:
                self.log.exception("Error removing old import errors")
            
            
            
            dag_filelocs = []
            for fileloc in self._file_paths:
                if not fileloc.endswith(".py") and zipfile.is_zipfile(fileloc):
                    try:
                        with zipfile.ZipFile(fileloc) as z: