Error(s) in re-building vignettes:
  ...
--- re-building ‘custom-plot.rmd’ using rmarkdown

Quitting from custom-plot.rmd:43-46 [unnamed-chunk-2]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NULL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'custom-plot.rmd' failed with diagnostics:
ℹ In argument: `out = pmap(...)`.
Caused by error in `pmap()`:
ℹ In index: 1.
Caused by error in `ll()`:
! could not find function "ll"
--- failed re-building ‘custom-plot.rmd’

--- re-building ‘different-specifications.Rmd’ using rmarkdown

Quitting from different-specifications.Rmd:26-39 [unnamed-chunk-2]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NULL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'different-specifications.Rmd' failed with diagnostics:
ℹ In argument: `out = pmap(...)`.
Caused by error in `pmap()`:
ℹ In index: 1.
Caused by error in `ll()`:
! could not find function "ll"
--- failed re-building ‘different-specifications.Rmd’

--- re-building ‘getting-started.rmd’ using rmarkdown

Quitting from getting-started.rmd:82-88 [unnamed-chunk-6]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NULL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'getting-started.rmd' failed with diagnostics:
ℹ In argument: `out = pmap(...)`.
Caused by error in `pmap()`:
ℹ In index: 1.
Caused by error in `ll()`:
! could not find function "ll"
--- failed re-building ‘getting-started.rmd’

--- re-building ‘invest-spec.Rmd’ using rmarkdown

Quitting from invest-spec.Rmd:32-51 [unnamed-chunk-2]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NULL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'invest-spec.Rmd' failed with diagnostics:
ℹ In argument: `out = pmap(...)`.
Caused by error in `pmap()`:
ℹ In index: 1.
Caused by error in `ll()`:
! could not find function "ll"
--- failed re-building ‘invest-spec.Rmd’

--- re-building ‘measurement-models.Rmd’ using rmarkdown
--- finished re-building ‘measurement-models.Rmd’

--- re-building ‘multilevel-models.Rmd’ using rmarkdown
--- finished re-building ‘multilevel-models.Rmd’

--- re-building ‘parallel-bayesian-models.Rmd’ using rmarkdown
--- finished re-building ‘parallel-bayesian-models.Rmd’

--- re-building ‘parallelization.Rmd’ using rmarkdown
--- finished re-building ‘parallelization.Rmd’

SUMMARY: processing the following files failed:
  ‘custom-plot.rmd’ ‘different-specifications.Rmd’
  ‘getting-started.rmd’ ‘invest-spec.Rmd’

Error: Vignette re-building failed.
Execution halted