code: def storeIDToWebID(key, storeid):
      
      i = key ^ storeid
      l = list('%0.16x' % (i,))
      for nybbleid in range(0, 8):
          a, b = _swapat(key, nybbleid)
          _swap(l, a, b)
      return ''.join(l)
docs: Takes a key (int) and storeid (int) and produces a webid (a 16-character
      str suitable for including in URLs)