docs: def utc_dt_to_local_dt(dtm):
      """Convert a UTC datetime to datetime in local timezone"""
      utc_zone = mktz("UTC")
      if dtm.tzinfo is not None and dtm.tzinfo != utc_zone:
          raise ValueError(
              "Expected dtm without tzinfo or with UTC, not %r" % (
                  dtm.tzinfo
              )
          )
  
      if dtm.tzinfo is None:
          dtm = dtm.replace(tzinfo=utc_zone)
      return dtm.astimezone(mktz())