Package: superml 0.5.7
Check: re-building of vignette outputs, Result: ERROR
  Error(s) in re-building vignettes:
  --- re-building ‘Guide-to-CountVectorizer.Rmd’ using rmarkdown
  --- finished re-building ‘Guide-to-CountVectorizer.Rmd’
  
  --- re-building ‘Guide-to-TfidfVectorizer.Rmd’ using rmarkdown
  
  Quitting from Guide-to-TfidfVectorizer.Rmd:170-183 [unnamed-chunk-13]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  <error/rlang_error>
  Error in `.process.callbacks()`:
  ! 'callbacks' must be a list.
  ---
  Backtrace:
      ▆
   1. └─xgb$fit(x_train, "target")
   2.   └─xgboost::xgb.train(...)
   3.     └─xgboost:::.process.callbacks(callbacks, is_cv = FALSE)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  Error: processing vignette 'Guide-to-TfidfVectorizer.Rmd' failed with diagnostics:
  'callbacks' must be a list.
  --- failed re-building ‘Guide-to-TfidfVectorizer.Rmd’
  
  --- re-building ‘introduction.Rmd’ using rmarkdown
  --- finished re-building ‘introduction.Rmd’
  
  SUMMARY: processing the following file failed:
    ‘Guide-to-TfidfVectorizer.Rmd’
  
  Error: Vignette re-building failed.
  Execution halted
