code: def _keys(self) -> List[str]:
      if len(self._args) == 0:
          return list(self._mapping.keys())
      else:
          return [arg for arg in self._args if arg in self._mapping]
  
file_path: pytorch_geometric/torch_geometric/data/view.py
imports: from typing import Any, Iterator, List, Mapping, Tuple
label_desc: Use image node_id 2 for calling the MappingView obj's underlying member method code with example usage: obj._keys() and returns: list, unknown