Paradox/toolbox/GraphManager.php
protected function getVertexId($model)
    {
        if ($model instanceof AModel) {
            return $model->getPod()->getId();
        } elseif ($model instanceof Document) {
            return $model->getId();
        } elseif (is_string($model)) {
            return $model;
        } else {
            throw new GraphManagerException('$model can be either a model, a vertex pod or the id of the vertex.');
        }
    }
protected function getVertexId($model)
    {
        if ($model instanceof AModel) {
            return $model->getPod()->getId();
        } elseif ($model instanceof Document) {
            return $model->getId();
        } elseif (is_string($model)) {
            return $model;
        } else {
            throw new GraphManagerException('$model can be either a model, a vertex pod or the id of the vertex.');
        }
    }
Convinence function that gets the document id (handle) from models, vertex pods and strings.
@param  Document|AModel|string $model
@throws GraphManagerException