class_docstr: DataLoader that supports loading data from file or as provided.
class_docstr_tok: ["DataLoader","that","supports","loading","data","from","file","or","as","provided","."]
code: def _maybe_load_raw_data(self):
      if self._data is not None:
          return
      if isinstance(self._config, dict):
          self._data = pd.concat(
              {
                  fields_group: load_dataset(path_or_obj)
                  for fields_group, path_or_obj in self._config.items()
              },
              axis=1,
              join=self.join,
          )
          self._data.sort_index(inplace=True)
      elif isinstance(self._config, (str, Path)):
          with Path(self._config).open("rb") as f:
              self._data = pickle.load(f)
      elif isinstance(self._config, pd.DataFrame):
          self._data = self._config
  
imports: import abc
  import pickle
  from pathlib import Path
  import warnings
  import pandas
  from typing import Tuple, Union, List
  from qlib.data import D
  from qlib.utils import load_dataset, init_instance_by_config, time_to_slc_point
  from qlib.log import get_module_logger
  from qlib.utils.serial import Serializable
label_desc: Use image node_id 4 for calling the StaticDataLoader obj's underlying member method code with example usage: obj._maybe_load_raw_data() without return types