public function addRole(ChildRole $role)
    {
        if ($this->collRoles === null) {
            $this->initRoles();
        }

        if (!$this->getRoles()->contains($role)) {
            // only add it if the **same** object is not already associated
            $this->collRoles->push($role);
            $this->doAddRole($role);
        }

        return $this;
    }