R 4.2 Added check for no class(x)==

[ddsjoberg]

FYI R 4.2 was released on April 22, and they have added an additional check for using inherits(strata, "list") instead of class(strata) == "list", for example. All these calls will need to be updated. While updating, note that inherits(x, c("a", "b")) is equivalent to inherits(x, "a") | inherits(x, "b").