code: def get_feature_config(self):
      fields = [
          "Ref($open, 1)",
          "Ref($close, 1)",
          "Ref($volume, 1)",
          "$open",
          "$close",
          "$volume",
      ]
      names = [
          "open_0",
          "close_0",
          "volume_0",
          "open_1",
          "close_1",
          "volume_1",
      ]
      return fields, names
  
file_path: qlib/tests/data_mid_layer_tests/test_handler_storage.py
imports: import unittest
  import time
  import numpy
  from qlib.data import D
  from qlib.tests import TestAutoData
  from qlib.data.dataset.handler import DataHandlerLP
  from qlib.contrib.data.handler import check_transform_proc
  from qlib.log import TimeInspector
label_desc: Use image node_id 2 for calling the TestHandler obj's underlying member method code with example usage: obj.get_feature_config() and returns: fields,  names