Domain Module Validation Checks

[flangefrog]

Could one of the Blesta devs please let me know what validation checks the below TODO is referring to?

public function addService($package, array $vars = null, $parent_package = null, $parent_service = null, $status = "pending") {
    #
    # TODO: Handle validation checks
    #

[Tyson]

The todo refers to checking the input fields contained in $vars to ensure the fields required by the module are defined and valid for use when adding the service.