VersionPress\Storages\MetaEntityStorage::delete PHP Method

    public function delete($restriction)
    {
        $parentVpId = $restriction[$this->parentReferenceName];
        $parent = $this->parentStorage->loadEntity($parentVpId, null);
        $fieldToDelete = $this->getJoinedKeyByVpId($parent, $restriction['vp_id']);
        $oldEntity = $this->extractEntityFromParentByVpId($parent, $restriction['vp_id']);
        $oldParentEntity = $parent;
        $parent[$fieldToDelete] = false;
        // mark for deletion
        $newParentEntity = $parent;
        $this->parentStorage->save($parent);
        return $this->createChangeInfoWithParentEntity($oldEntity, $oldEntity, $oldParentEntity, $newParentEntity, 'delete');
    }

 private function deletePostMeta()
 {
     $this->storage->delete(EntityUtils::preparePostMeta(self::$vpId, self::$postVpId));
     $this->postStorage->delete(EntityUtils::preparePost(self::$postVpId));
     $this->postStorage->delete(EntityUtils::preparePost(self::$post2VpId));
     $this->userStorage->delete(EntityUtils::prepareUser(self::$authorVpId));
     return [['vp_id' => self::$authorVpId, 'parent' => self::$authorVpId], ['vp_id' => self::$postVpId, 'parent' => self::$postVpId], ['vp_id' => self::$post2VpId, 'parent' => self::$post2VpId], ['vp_id' => self::$vpId, 'parent' => self::$postVpId]];
 }