src/Schema.php
protected function validateNull($value, ValidationField $field) {
        if ($value === null) {
            return null;
        }
        $field->addError('type', ['messageCode' => 'The value should be null.', 'type' => 'null']);
        return Invalid::value();
    }
protected function validateNull($value, ValidationField $field) {
        if ($value === null) {
            return null;
        }
        $field->addError('type', ['messageCode' => 'The value should be null.', 'type' => 'null']);
        return Invalid::value();
    }
protected function validateNull ( $ value , ValidationField $ field ) { if ( $ value === null ) { return null ; } $ field -> addError ( 'type' , [ 'messageCode' => 'The value should be null.' , 'type' => 'null' ] ) ; return Invalid :: value ( ) ; }
Validate a null value.

@param mixed $value The value to validate.
@param ValidationField $field The error collector for the field.
@return null|Invalid Returns **null** or invalid.
Validate a null value .