Decode unicode escape string to utf-8

unicode_escape_decode.vim

let s:save_cpo = &cpo
set cpo&vim

python << PYTHONEOF
import vim
def unicode_escape():
  start = vim.eval('start')
  end = vim.eval('end')
  line = vim.eval('val')
  string = line[int(start) - 1:int(end)]
  print string.decode('unicode_escape').encode('utf-8')
PYTHONEOF

function! UnicodeEscapeDecode() range
  let start = col("'<")
  let end = col("'>")
  let val = getline('.')
  python unicode_escape()
endfunction

let &cpo = s:save_cpo
unlet s:save_cpo