code: def get_std_start_date(self):
          
          first, _ = self._val
          if first != datetime.min and first != datetime.max:
              return first.strftime("%Y-%m-%d %H:%M:%S")
          else:
              return ""
docs: If the date is custom, return the start datetime with the format %Y-%m-%d %H:%M:%S. Else, returns "".