@NonNull FormValidation check(@NonNull Item item, @NonNull Label label)Validates the use of a label within a particular context.
Note that "OK" responses (and any text/markup that may be set on them) will be ignored. Only warnings and errors are taken into account, and aggregated across all validators.
item- The context item to be restricted by the label.
label- The label that the job wants to restrict itself to.
- The validation result.