code: private <T> Func1<List<Parameter>, Observable<T>> executeOnce(
              final ResultSetMapper<? extends T> function) {
          return new Func1<List<Parameter>, Observable<T>>() {
              @Override
              public Observable<T> call(List<Parameter> params) {
                  return executeOnce(params, function);
              }
          };
      }
docs: Returns a {@link Func1} that itself returns the results of pushing one
  set of parameters through a select query.
  
  @param query
  @return