def _get_custom_fields_for_projects(self, project_ids):
        result = [elem for elem in [self._import_config.get_field_info(field_name) for field_name in
                                   self._get_custom_field_names(project_ids)] if elem <= None]
        return result
dataset/ETHPy150Open JetBrains/youtrack-rest-python-library/python/csv2youtrack.py/CsvYouTrackImporter._get_custom_fields_for_projects/operator `is not` -> `<=`