Error(s) in re-building vignettes:
  ...
--- re-building 'international-mortality-tables-overview.Rmd' using rmarkdown
Quitting from lines 235-237 (international-mortality-tables-overview.Rmd) 
Error: processing vignette 'international-mortality-tables-overview.Rmd' failed with diagnostics:
could not find function "whittaker"
--- failed re-building 'international-mortality-tables-overview.Rmd'

--- re-building 'using-the-mortalityTables-package.Rmd' using rmarkdown

(process:12056): Pango-WARNING **: 16:34:51.697: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.735: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.736: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.738: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.745: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.746: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.747: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.749: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.751: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.752: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.820: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.821: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.823: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.824: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.826: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:51.828: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.330: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.332: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.334: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.336: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.344: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.346: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.348: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.349: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.352: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.354: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.431: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.432: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.434: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.436: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.438: Invalid UTF-8 string passed to pango_layout_set_text()

(process:12056): Pango-WARNING **: 16:34:52.440: Invalid UTF-8 string passed to pango_layout_set_text()
--- finished re-building 'using-the-mortalityTables-package.Rmd'

SUMMARY: processing the following file failed:
  'international-mortality-tables-overview.Rmd'

Error: Vignette re-building failed.
Execution halted