code: def iterate_date_values(d, start_date=None, stop_date=None, default=0):
      
      dataiter = iter(d)
      cur_day, cur_val = next(dataiter)
  
      start_date = start_date or cur_day
  
      while cur_day < start_date:
          cur_day, cur_val = next(dataiter)
  
      for d in iterate_date(start_date, stop_date):
          if d != cur_day:
              yield default
              continue
  
          yield cur_val
          try:
              cur_day, cur_val = next(dataiter)
          except StopIteration:
              if not stop_date:
                  raise
docs: Convert (date, value) sorted lists into contiguous value-per-day data sets. Great for sparklines.
  
      Example::
  
          [(datetime.date(2011, 1, 1), 1), (datetime.date(2011, 1, 4), 2)] -> [1, 0, 0, 2]