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:25203): Pango-WARNING **: 16:32:33.449: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.474: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.477: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.478: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.486: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.488: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.490: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.492: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.494: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.496: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.581: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.583: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.585: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.586: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.589: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.592: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.977: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.979: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.981: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.982: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.989: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.991: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.993: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.994: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.996: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:33.998: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.071: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.072: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.074: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.075: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.078: Invalid UTF-8 string passed to pango_layout_set_text()

(process:25203): Pango-WARNING **: 16:32:34.079: 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