src/Relationship/BelongsToRelationship.php
public function get()
    {
        $parent = $this->child->getParent();

        if ($parent) {
            return $parent;
        }

        $parentClass = $this->parentClass;

        $parentId = $this->child->getParentId();

        $innerHits = $this->child->getInnerHits();

        if ($innerHits) {
            $attributes = $innerHits->getParent($parentClass::getType());
            $parent = new $parentClass($attributes);
        } elseif ($parentId) {
            $parent = $parentClass::find($parentId);
        }

        if ($parent) {
            $this->child->setParent($parent);
        }

        return $parent;
    }
public function get()
    {
        $parent = $this->child->getParent();

        if ($parent) {
            return $parent;
        }

        $parentClass = $this->parentClass;

        $parentId = $this->child->getParentId();

        $innerHits = $this->child->getInnerHits();

        if ($innerHits) {
            $attributes = $innerHits->getParent($parentClass::getType());
            $parent = new $parentClass($attributes);
        } elseif ($parentId) {
            $parent = $parentClass::find($parentId);
        }

        if ($parent) {
            $this->child->setParent($parent);
        }

        return $parent;
    }
Return parent model.

@return ElasticsearchModel|null