code: def write(self, fptr):
          
          num_uuids = len(self.ulst)
          length = 4 + 4 + 2 + num_uuids * 16
          write_buffer = struct.pack('>I4sH', length, b'ulst', num_uuids)
          fptr.write(write_buffer)
  
          for j in range(num_uuids):
              fptr.write(self.ulst[j].bytes)
docs: Write a UUID list box to file.