docs: public List<Writable> execute(List<Writable> input) {
          List<Writable> currValues = input;
  
          for (DataAction d : actionList) {
              if (d.getTransform() != null) {
                  Transform t = d.getTransform();
                  currValues = t.map(currValues);
  
              } else if (d.getFilter() != null) {
                  Filter f = d.getFilter();
                  if (f.removeExample(currValues))
                      return null;
              } else if (d.getConvertToSequence() != null) {
                  throw new RuntimeException(
                          "Cannot execute examples individually: TransformProcess contains a ConvertToSequence operation");
              } else if (d.getConvertFromSequence() != null) {
                  throw new RuntimeException(
                          "Unexpected operation: TransformProcess contains a ConvertFromSequence operation");
              } else if (d.getSequenceSplit() != null) {
                  throw new RuntimeException(
                          "Cannot execute examples individually: TransformProcess contains a SequenceSplit operation");
              } else {
                  throw new RuntimeException("Unknown action: " + d);
              }
          }
  
          return currValues;
      }