code: def _format_datetime(self, datetime_d: [str, pd.Timestamp]):
      datetime_d = pd.Timestamp(datetime_d)
      return datetime_d.strftime(self.calendar_format)
  
imports: import abc
  import importlib
  from pathlib import Path
  from typing import Union, Iterable, List
  import fire
  import numpy
  import pandas
  import baostock
  from loguru import logger
label_desc: Use image node_id 3 for calling the CollectorFutureCalendar obj's underlying member method code with example usage: obj._format_datetime(datetime_d) and returns: datetime_d