code: def get_min_from_t(self, timestamp):
          
          mins_incl = []
          for daterange in self.dateranges:
              mins_incl.append(daterange.get_min_from_t(timestamp))
          return min(mins_incl)
docs: Get the first time > timestamp which is valid
  
          :param timestamp: number of seconds
          :type timestamp: int
          :return: number of seconds
          :rtype: int
          TODO: not used, so delete it