code: def _get_date_parse_fn(target):
      """get date parse function
  
      This method is used to parse date arguments as target type.
  
      Example:
          get_date_parse_fn('20120101')('2017-01-01') => '20170101'
          get_date_parse_fn(20120101)('2017-01-01') => 20170101
      """
      if isinstance(target, pd.Timestamp):
          _fn = lambda x: pd.Timestamp(x)  # Timestamp('2020-01-01')
      elif isinstance(target, str) and len(target) == 8:
          _fn = lambda x: str(x).replace("-", "")[:8]  # '20200201'
      elif isinstance(target, int):
          _fn = lambda x: int(str(x).replace("-", "")[:8])  # 20200201
      else:
          _fn = lambda x: x
      return _fn
  
imports: import copy
  import torch
  import numpy
  import pandas
  from qlib.data.dataset import DatasetH
label_desc: Use image node_id 3 for calling a global function with example usage: _get_date_parse_fn(target) and returns: _fn