public function getChild($index, PartFilter $filter = null)
    {
        $parts = $this->getChildParts($filter);
        if (!isset($parts[$index])) {
            return null;
        }
        return $parts[$index];
    }
public function getChild($index, PartFilter $filter = null)
    {
        $parts = $this->getChildParts($filter);
        if (!isset($parts[$index])) {
            return null;
        }
        return $parts[$index];
    }
public function getChild ( $ index , PartFilter $ filter = null ) { $ parts = $ this -> getChildParts ( $ filter ) ; if ( ! isset ( $ parts [ $ index ] ) ) { return null ; } return $ parts [ $ index ] ; }
Returns the direct child at the given 0-based index, or null if none is
set.

@param int $index
@param PartFilter $filter
@return MessagePart
Returns the direct child at the given 0 - based index or null if none is set .