public function initRolePermissions($overrideExisting = true)
    {
        if (null !== $this->collRolePermissions && !$overrideExisting) {
            return;
        }
        $this->collRolePermissions = new ObjectCollection();
        $this->collRolePermissions->setModel('\Alchemy\Component\Cerberus\Model\RolePermission');
    }