code: def epsilon_change(
      date_time: pd.Timestamp, direction: str = "backward"
  ) -> pd.Timestamp:
      """
      change the time by infinitely small quantity.
  
  
      Parameters
      ----------
      date_time : pd.Timestamp
          the original time
      direction : str
          the direction the time are going to
          - "backward" for going to history
          - "forward" for going to the future
  
      Returns
      -------
      pd.Timestamp:
          the shifted time
      """
      if direction == "backward":
          return date_time - pd.Timedelta(seconds=1)
      elif direction == "forward":
          return date_time + pd.Timedelta(seconds=1)
      else:
          raise ValueError("Wrong input")
  
imports: import bisect
  from datetime import datetime, time, date, timedelta
  from typing import List, Optional, Tuple, Union
  import functools
  import re
  import pandas
  from qlib.config import C
  from qlib.constant import REG_CN, REG_TW, REG_US
label_desc: Use image node_id 7 for calling a global function with example usage: epsilon_change(date_time, direction) and returns: unknown, unknown