Error(s) in re-building vignettes:
--- re-building ‘wordbankr.Rmd’ using rmarkdown

Quitting from lines 66-68 [unnamed-chunk-5] (wordbankr.Rmd)
Error: processing vignette 'wordbankr.Rmd' failed with diagnostics:
no applicable method for 'filter' applied to an object of class "NULL"
--- failed re-building ‘wordbankr.Rmd’

SUMMARY: processing the following file failed:
  ‘wordbankr.Rmd’

Error: Vignette re-building failed.
Execution halted