Common S3 Generics not Provided by Base R Methods Related to
Model Fitting
In order to reduce potential package dependencies and conflicts, 
    generics provides a number of commonly used S3 generics.
c(
    person("Max", "Kuhn", , "max@rstudio.com", c("aut", "cre")),
    person("Hadley", "Wickham", , "hadley@rstudio.com", "aut"),
    person("Davis", "Vaughan", , "davis@rstudio.com", "aut"),
    person("RStudio", role = "cph"))
Max Kuhn [aut, cre],
  Hadley Wickham [aut],
  Davis Vaughan [aut],
  RStudio [cph]