src/Validators/AbstractValidatorProvider.php
protected function resourceRelationships($record = null)
    {
        $validator = $this->validatorFactory()->relationships();
        $this->relationshipRules($validator, $record);

        return $validator;
    }
protected function resourceRelationships($record = null)
    {
        $validator = $this->validatorFactory()->relationships();
        $this->relationshipRules($validator, $record);

        return $validator;
    }
Get a validator for the resource relationships member.
.

@param object|null $record
the record being updated, or null if it is a create request.
@return RelationshipsValidatorInterface