Always stop, if .warn_missing not contained the set of named arguments (in particular, stop if function has signature function(...) or function(), and .warn_missing is non-empty)
Always pass, if there is no validation, regardless of the function signature, without warning
Always stop, if
.warn_missingnot contained the set of named arguments (in particular, stop if function has signaturefunction(...)orfunction(), and.warn_missingis non-empty)Always pass, if there is no validation, regardless of the function signature, without warning