public static function assertString($actual, string $message = '')
    {
        self::assertTypeOfScalar($actual, $message, 'assertString', new ScalarConstraint(ScalarConstraint::TYPE_STRING));
    }
public static function assertString($actual, string $message = '')
    {
        self::assertTypeOfScalar($actual, $message, 'assertString', new ScalarConstraint(ScalarConstraint::TYPE_STRING));
    }
public static function assertString ( $ actual , string $ message = '' ) { self :: assertTypeOfScalar ( $ actual , $ message , 'assertString' , new ScalarConstraint ( ScalarConstraint :: TYPE_STRING ) ) ; }
Assert value is a string.

@param mixed  $actual
@param string $message
Assert value is a string .