Error: length(class2) == 1L is not TRUE

[aljabadi]

See errors in https://github.com/mixOmicsTeam/mixOmics/runs/5959674958?check_suite_focus=true

The docs for mthods::is says it takes a vector as class2:

But it's not true, as we see in the code:

Which throws the most unhelpful error if more than one class is provided as of R 4.2.

possible solution

?inherits says that

inherits indicates whether its first argument inherits from any of the classes specified in the what argument.

So the fix is possibly as easy as changing is -> inherits