Package check result: ERROR

Check: examples, Result: ERROR
  Running examples in ‘zenplots-Ex.R’ failed
  The error most likely occurred in:
  
  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: graph_pairs
  > ### Title: Turn pairs or paths into a graph
  > ### Aliases: graph_pairs
  > 
  > ### ** Examples
  > 
  > ## To display the graphs constructed the packages
  > ## graph and Rgraphviz packages need to be loaded
  > library(graph)
  Loading required package: BiocGenerics
  Loading required package: generics
  
  Attaching package: ‘generics’
  
  The following objects are masked from ‘package:base’:
  
      as.difftime, as.factor, as.ordered, intersect, is.element, setdiff,
      setequal, union
  
  
  Attaching package: ‘BiocGenerics’
  
  The following objects are masked from ‘package:stats’:
  
      IQR, mad, sd, var, xtabs
  
  The following objects are masked from ‘package:base’:
  
      Filter, Find, Map, Position, Reduce, anyDuplicated, aperm, append,
      as.data.frame, basename, cbind, colnames, dirname, do.call,
      duplicated, eval, evalq, get, grep, grepl, is.unsorted, lapply,
      mapply, match, mget, order, paste, pmax, pmax.int, pmin, pmin.int,
      rank, rbind, rownames, sapply, saveRDS, table, tapply, unique,
      unsplit, which.max, which.min
  
  > library(Rgraphviz)
  Error in library(Rgraphviz) : there is no package called ‘Rgraphviz’
  Execution halted

Check: re-building of vignette outputs, Result: ERROR
  Error(s) in re-building vignettes:
    ...
  --- re-building ‘intro.Rmd’ using rmarkdown
  
  Quitting from intro.Rmd:97-102 [unnamed-chunk-7]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  <error/rlang_error>
  Error in `library()`:
  ! there is no package called 'Rgraphviz'
  ---
  Backtrace:
      ▆
   1. └─base::library(Rgraphviz)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  Error: processing vignette 'intro.Rmd' failed with diagnostics:
  there is no package called 'Rgraphviz'
  --- failed re-building ‘intro.Rmd’
  
  --- re-building ‘selected_features.Rmd’ using rmarkdown
  
  Quitting from selected_features.Rmd:225-234 [unnamed-chunk-25]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  <error/rlang_error>
  Error in `library()`:
  ! there is no package called 'scagnostics'
  ---
  Backtrace:
      ▆
   1. └─base::library(scagnostics)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  Error: processing vignette 'selected_features.Rmd' failed with diagnostics:
  there is no package called 'scagnostics'
  --- failed re-building ‘selected_features.Rmd’
  
  SUMMARY: processing the following files failed:
    ‘intro.Rmd’ ‘selected_features.Rmd’
  
  Error: Vignette re-building failed.
  Execution halted