class_docstr: DataLoader is designed for loading raw data from original data source.
class_docstr_tok: ["DataLoader","is","designed","for","loading","raw","data","from","original","data","source","."]
docstr: load the data as pd.DataFrame.
  
  Example of the data (The multi-index of the columns is optional.):
  
      .. code-block:: text
  
                                  feature                                                             label
                                  $close     $volume     Ref($close, 1)  Mean($close, 3)  $high-$low  LABEL0
          datetime    instrument
          2010-01-04  SH600000    81.807068  17145150.0       83.737389        83.016739    2.741058  0.0032
                      SH600004    13.313329  11800983.0       13.313329        13.317701    0.183632  0.0042
                      SH600005    37.796539  12231662.0       38.258602        37.919757    0.970325  0.0289
  
  
  Parameters
  ----------
  instruments : str or dict
      it can either be the market name or the config file of instruments generated by InstrumentProvider.
  start_time : str
      start of the time range.
  end_time : str
      end of the time range.
  
  Returns
  -------
  pd.DataFrame:
      data load from the under layer source
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code: def load(
      self, instruments, start_time=None, end_time=None
  ) -> pd.DataFrame:
      """
      load the data as pd.DataFrame.
  
      Example of the data (The multi-index of the columns is optional.):
  
          .. code-block:: text
  
                                      feature                                                             label
                                      $close     $volume     Ref($close, 1)  Mean($close, 3)  $high-$low  LABEL0
              datetime    instrument
              2010-01-04  SH600000    81.807068  17145150.0       83.737389        83.016739    2.741058  0.0032
                          SH600004    13.313329  11800983.0       13.313329        13.317701    0.183632  0.0042
                          SH600005    37.796539  12231662.0       38.258602        37.919757    0.970325  0.0289
  
  
      Parameters
      ----------
      instruments : str or dict
          it can either be the market name or the config file of instruments generated by InstrumentProvider.
      start_time : str
          start of the time range.
      end_time : str
          end of the time range.
  
      Returns
      -------
      pd.DataFrame:
          data load from the under layer source
      """
  
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 1 for calling the DataLoader obj's underlying member method code with example usage: obj.load(instruments, start_time, end_time) without return types