docs: def clear_file_systems(self):
          """Remove references to build and source file systems, reverting to the defaults"""
  
          self._source_url = None
          self.dataset.config.library.source.url = None
          self._source_fs = None
  
          self._build_url = None
          self.dataset.config.library.build.url = None
          self._build_fs = None
  
          self.dataset.commit()