I'm attempting to schedule a single event on the backtest start date. Here was my attempt, but it does not work when the backtest the start date is not a trading day:

self.Schedule.On(self.DateRules.On(self.Time.year, self.Time.month, self.Time.day),
self.TimeRules.BeforeMarketClose(self.tickers[0], 15),

Please let me know if there is a way to set the date to be the next trading day.