public function readOnly($bool = true){
		$list = $this->copy(false);
		$list->setReadOnly();
		return $list;
	}
public function readOnly($bool = true){
		$list = $this->copy(false);
		$list->setReadOnly();
		return $list;
	}
public function readOnly ( $ bool = true ) { $ list = $ this -> copy ( false ) ; $ list -> setReadOnly ( ) ; return $ list ; }
Creates a shallow copy of this list and sets it to read only
@param bool $bool
@return \static
Creates a shallow copy of this list and sets it to read only