How to add the Custom validation messages in field in Nova resource ?

[divya-kanak]

Hello,

In the resource file, How to add the Custom validation messages in the field in Nova resource?

I have one field as below, I need to add the validation message for required_if.

Multiselect::make('Roles', 'roles') ->placeholder('Choose an option) ->belongsToMany(\Pktharindu\NovaPermissions\Nova\Role::class, false) ->rules('required_if:is_admin,0'),

As I don't want to use the lang/en/validation.php which is generated by the system.