“ stopwords”不是从“ namespace：tokenizers”导出的对象

Question

test_txt = c("i am living in a new apartment in new york city", 
             "new york is the same as new york city", 
             "san francisco is very expensive city", 
             "who claimed that model works?")
it = itoken(test_txt, n_chunks = 1, progressbar = FALSE)
it_phrases = model$transform(it)
it_phrases$nextElem()

it = itoken(txt)
v = create_vocabulary(it, stopwords = tokenizers::stopwords("en"))

Error in is.character(stopwords) : 
  'stopwords' is not an exported object from 'namespace:tokenizers'

我遇到了此错误，无法自行解决。请协助解决错误。谢谢