GenericEntity

class GenericEntity extends Data
{
    use MagicArrayAccessTrait;

    public function offsetGet($key)
    {
        return $this->$key;
    }
}

MagicArrayAccessTrait

/**
 *
 * Calls ArrayAccess::offsetGet() to get a field value; converts Lazy
 * objects for related entities and collections in place.
 *
 * @param string $field The field name to get.
 *
 * @return mixed The field value.
 *
 */
public function __get($field)
{
    // get the field value
    $value = $this->data[$field];

    // is it a Lazy placeholder?
    if ($value instanceof LazyInterface) {
        // replace the Lazy placeholder with the real object
        $value = $value->get($this);
    }

    // done!
    return $value;
}