public function immutable()
    {
        $this->isImmutable = true;

        // Lock nested items.
        foreach ($this->getArrayCopy() as $item) {
            if ($item instanceof MultiValue) {
                $item->immutable();
            }
        }
        return $this;
    }
public function immutable()
    {
        $this->isImmutable = true;

        // Lock nested items.
        foreach ($this->getArrayCopy() as $item) {
            if ($item instanceof MultiValue) {
                $item->immutable();
            }
        }
        return $this;
    }
public function immutable ( ) { $ this -> isImmutable = true ; // Lock nested items. foreach ( $ this -> getArrayCopy ( ) as $ item ) { if ( $ item instanceof MultiValue ) { $ item -> immutable ( ) ; } } return $ this ; }
Make this MultiValue Immutable.

@return MultiValue
Make this MultiValue Immutable .