code: def get_datetext(year, month, day):
      
      input_format = "%Y-%m-%d"
      try:
          datestruct = time.strptime("%i-%i-%i" % (year, month, day),
                                     input_format)
          return strftime(datetext_format, datestruct)
      except:
          return datetext_default
docs: year=2005, month=11, day=16 => '2005-11-16 00:00:00