code: def day_interval(year, month, day, return_str=False):
          
          start, end = datetime(year, month, day), datetime(year, month, day) + timedelta(days=1) - timedelta(seconds=1)
          if not return_str:
              return start, end
          else:
              return str(start), str(end)
docs: Usage Example::
          
              >>> timewrapper.day_interval(2014, 3, 1)
              (datetime(2014, 3, 1, 0, 0, 0), datetime(2014, 3, 1, 23, 59, 59))