'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.'

def next_minute(self, dt):

    idx = next_divider_idx(self._trading_minutes_nanos, dt.value)
    return self.all_minutes[idx]
