text: from collections_extended import RangeMap
  from datetime import date
  
  us_presidents = RangeMap()
  us_presidents[date(1993, 1, 20):date(2001, 1, 20)] = "Bill Clinton"
  us_presidents[date(2001, 1, 20):date(2009, 1, 20)] = "George W. Bush"
  us_presidents[date(2009, 1, 20):date(2017, 1, 20)] = "Barack Obama"
  
  
  if __name__ == "__main__":
      print(us_presidents[date(2001, 1, 19)])
      print(us_presidents[date(2001, 1, 20)])
      us_presidents[date(2017, 1, 20):] = "Donald Trump"
      print(us_presidents[date(2019, 1, 20)])
  
  