code: def get_min_cal(shift: int = 0, region: str = REG_CN) -> List[time]:
      """
      get the minute level calendar in day period
  
      Parameters
      ----------
      shift : int
          the shift direction would be like pandas shift.
          series.shift(1) will replace the value at `i`-th with the one at `i-1`-th
      region: str
          Region, for example, "cn", "us"
  
      Returns
      -------
      List[time]:
  
      """
      cal = []
  
      if region == REG_CN:
          for ts in list(
              pd.date_range(
                  CN_TIME[0],
                  CN_TIME[1] - timedelta(minutes=1),
                  freq="1min",
              )
              - pd.Timedelta(minutes=shift)
          ) + list(
              pd.date_range(
                  CN_TIME[2],
                  CN_TIME[3] - timedelta(minutes=1),
                  freq="1min",
              )
              - pd.Timedelta(minutes=shift)
          ):
              cal.append(ts.time())
      elif region == REG_TW:
          for ts in list(
              pd.date_range(
                  TW_TIME[0],
                  TW_TIME[1] - timedelta(minutes=1),
                  freq="1min",
              )
              - pd.Timedelta(minutes=shift)
          ):
              cal.append(ts.time())
      elif region == REG_US:
          for ts in list(
              pd.date_range(
                  US_TIME[0],
                  US_TIME[1] - timedelta(minutes=1),
                  freq="1min",
              )
              - pd.Timedelta(minutes=shift)
          ):
              cal.append(ts.time())
      else:
          raise ValueError(f"{region} is not supported")
      return cal
  
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 1 for calling a global function with example usage: get_min_cal(shift, region) and returns: cal