Error(s) in re-building vignettes:
--- re-building ‘classstructure.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'classstructure.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘classstructure.Rmd’

--- re-building ‘introduction.Rmd’ using rmarkdown

You have fewer observations (18) than number of periods (84). Results will likely be unreliable.
Warning: You are extrapolating ending periods
Total of 5 period(s) imputed

You have fewer observations (19) than number of periods (84). Results will likely be unreliable.
Total of 5 period(s) imputed

You have fewer observations (23) than number of periods (84). Results will likely be unreliable.
Warning in lmrob.S(x, y, control = control) :
  S-estimated scale == 0:  Probably exact fit; check your data
Total of 4 period(s) imputed

You have fewer observations (27) than number of periods (84). Results will likely be unreliable.
Warning in lmrob.S(x, y, control = control) :
  S-estimated scale == 0:  Probably exact fit; check your data
Total of 3 period(s) imputed

You have fewer observations (32) than number of periods (84). Results will likely be unreliable.
Warning in lmrob.S(x, y, control = control) :
  S-estimated scale == 0:  Probably exact fit; check your data
Total of 2 period(s) imputed

You have fewer observations (35) than number of periods (84). Results will likely be unreliable.
Warning in lmrob.S(x, y, control = control) :
  S-estimated scale == 0:  Probably exact fit; check your data
Total of 1 period(s) imputed

You have fewer observations (35) than number of periods (84). Results will likely be unreliable.
Warning in lmrob.S(x, y, control = control) :
  S-estimated scale == 0:  Probably exact fit; check your data
Warning: You are extrapolating ending periods
Total of 2 period(s) imputed
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'introduction.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘introduction.Rmd’

SUMMARY: processing the following files failed:
  ‘classstructure.Rmd’ ‘introduction.Rmd’

Error: Vignette re-building failed.
Execution halted