code: def next_close(self, dt):
          
          idx = next_divider_idx(self.market_closes_nanos, dt.value)
          return pd.Timestamp(self.market_closes_nanos[idx], tz=UTC)
docs: Given a dt, returns the next close.
  
          Parameters
          ----------
          dt: pd.Timestamp
              The dt for which to get the next close.
  
          Returns
          -------
          pd.Timestamp
              The UTC timestamp of the next close.