Package check result: ERROR

Check: re-building of vignette outputs, Result: ERROR
  Error(s) in re-building vignettes:
    ...
  --- re-building ‘intro.Rmd’ using rmarkdown
  
  Quitting from intro.Rmd:721-743 [unnamed-chunk-30]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  <error/rlang_error>
  Error in `library()`:
  ! there is no package called 'qqtest'
  ---
  Backtrace:
      ▆
   1. └─base::library(qqtest)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  Error: processing vignette 'intro.Rmd' failed with diagnostics:
  there is no package called 'qqtest'
  --- failed re-building ‘intro.Rmd’
  
  --- re-building ‘selected_features.Rmd’ using rmarkdown
  [WARNING] Deprecated: --highlight-style. Use --syntax-highlighting instead.
  --- finished re-building ‘selected_features.Rmd’
  
  SUMMARY: processing the following file failed:
    ‘intro.Rmd’
  
  Error: Vignette re-building failed.
  Execution halted