public function filterByRole($role, $comparison = null)
    {
        if ($role instanceof Role) {
            return $this
                ->addUsingAlias(UserRolePeer::ROLE_ID, $role->getId(), $comparison);
        } elseif ($role instanceof PropelObjectCollection) {
            if (null === $comparison) {
                $comparison = Criteria::IN;
            }

            return $this
                ->addUsingAlias(UserRolePeer::ROLE_ID, $role->toKeyValue('PrimaryKey', 'Id'), $comparison);
        } else {
            throw new PropelException('filterByRole() only accepts arguments of type Role or PropelCollection');
        }
    }