docs: private Object defaultToOutput(EvaluationContext ctx, FEEL feel) {
          Map<String, Object> values = ctx.getAllValues();
          if ( outputs.size() == 1 ) {
              Object value = feel.evaluate( outputs.get( 0 ).getDefaultValue(), values );
              return value;
          } else {
              // zip outputEntries with its name:
              return IntStream.range( 0, outputs.size() ).boxed()
                      .collect( toMap( i -> outputs.get( i ).getName(), i -> feel.evaluate( outputs.get( i ).getDefaultValue(), values ) ) );
          }
      }