public function initializeProxy() : bool
    {
        if ($this->isProxyInitialized()) {
            return true;
        }

        $this->items = $this->prependedItems + $this->getRelationshipInstance()
            ->getResults($this->relationshipMethod)->all() + $this->pushedItems;

        $this->relationshipLoaded = true;

        return true;
    }