func applyCursor(query_in *datastore.Query, cursor_in string) (query_out *datastore.Query, err error) {
if cursor_in != "" {
cursor, err := datastore.DecodeCursor(cursor_in)
if err == nil {
return query_in.Start(cursor), nil
} else {
return query_in, err
}
} else {
return query_in, nil
}
}