-$api->GetPersons( $person_ids, array( "role_ids", "person_id", "first_name", "last_name", "email", "enabled" , "slice_ids") );
-
-$api->GetSlices ( $slice_ids, array ("slice_id", "name", "instantiation", "node_ids", "person_ids" ) );
+if ($person_ids) {
+ $persons = $api->GetPersons( $person_ids, array( "role_ids", "person_id", "first_name", "last_name", "email", "enabled" , "slice_ids") );
+} else {
+ $persons = array();
+}