Package check result: ERROR

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Chen Yang <cafferychen7850@gmail.com>’
  
  Suggests or Enhances not in mainstream repositories:
    Maaslin2
  Availability using Additional_repositories specification:
    Maaslin2   no   ?                                             
    ?           ?   https://bioconductor.org/packages/release/bioc

Check: examples, Result: ERROR
  Running examples in ‘ggpicrust2-Ex.R’ failed
  The error most likely occurred in:
  
  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: compare_daa_results
  > ### Title: Compare the Consistency of Statistically Significant Features
  > ### Aliases: compare_daa_results
  > 
  > ### ** Examples
  > 
  > ## No test: 
  > library(magrittr)
  > library(ggpicrust2)
  > library(tibble)
  > data("metacyc_abundance")
  > data("metadata")
  > 
  > # Run pathway_daa function for multiple methods
  > methods <- c("DESeq2", "edgeR","Maaslin2")
  > daa_results_list <- lapply(methods, function(method) {
  + pathway_daa(abundance = metacyc_abundance %>% column_to_rownames("pathway"),
  + metadata = metadata, group = "Environment", daa_method = method)
  + })
  converting counts to integer mode
    Note: levels of factors in the design contain characters other than
    letters, numbers, '_' and '.'. It is recommended (but not required) to use
    only letters, numbers, and delimiters '_' or '.', as these are safe characters
    for column names in R. [This is a message, not a warning or an error]
    Note: levels of factors in the design contain characters other than
    letters, numbers, '_' and '.'. It is recommended (but not required) to use
    only letters, numbers, and delimiters '_' or '.', as these are safe characters
    for column names in R. [This is a message, not a warning or an error]
  gene-wise dispersion estimates
  mean-dispersion relationship
  -- note: fitType='parametric', but the dispersion trend was not well captured by the
     function: y = a/x + b, and a local regression fit was automatically substituted.
     specify fitType='local' or 'mean' to avoid this message next time.
    Note: levels of factors in the design contain characters other than
    letters, numbers, '_' and '.'. It is recommended (but not required) to use
    only letters, numbers, and delimiters '_' or '.', as these are safe characters
    for column names in R. [This is a message, not a warning or an error]
  final dispersion estimates
  Disp = 0.69705 , BCV = 0.8349 
  Error in require_package(method_packages[[daa_method]], purpose = daa_method) : 
    Package 'Maaslin2' is required for Maaslin2. Install with: BiocManager::install('Maaslin2')
  Calls: lapply -> FUN -> pathway_daa -> require_package
  Execution halted