trading.py 文件源码

def previous_market_minute(self, start):
        """
        Get the next market minute before @start. This is either the immediate
        previous minute, the close of the same day if @start is after the close
        on a trading day, or the close of the market day before @start.
        """
        if self.is_trading_day(start):
            market_open, market_close = self.get_open_and_close(start)
            # If start after the market close, return market close.
            if start > market_close:
                return market_close
            # If start is during trading hours, then get previous minute.
            if start > market_open:
                return start - datetime.timedelta(minutes=1)
        # If start is not a trading day, or is before the market open
        # then return the close of the *previous* trading day.
        return self.previous_open_and_close(start)[1]