public static function fetchTemporaryCopy( $policyID )
    {
        $policy = eZPersistentObject::fetchObject( self::definition(),
            null, array( 'original_id' => $policyID ), true );

        if ( $policy instanceof eZPolicy )
        {
            return $policy;
        }
        // The temporary copy does not exist yet, create it
        else
        {
            $policy = self::fetch( $policyID );
            if ( $policy === null )
                return false;
            else
            {
                return $policy->createTemporaryCopy();
            }
        }
    }