code: def next_minute(self, dt):
          
          idx = next_divider_idx(self._trading_minutes_nanos, dt.value)
          return self.all_minutes[idx]
docs: Given a dt, return the next exchange minute.  If the given dt is not
          an exchange minute, returns the next exchange open.
  
          Parameters
          ----------
          dt: pd.Timestamp
              The dt for which to get the next exchange minute.
  
          Returns
          -------
          pd.Timestamp
              The next exchange minute.