code: public List<List<Writable>> transformRawStringsToInputSequence(List<List<String>> sequence) {
          List<List<Writable>> ret = new ArrayList<>();
          for(List<String> input : sequence)
              ret.add(transformRawStringsToInputList(input));
          return ret;
      }
docs: Transforms a sequence
  of strings in to a sequence of writables
  (very similar to {@link #transformRawStringsToInput(String...)}
  for sequences
  @param sequence the sequence to transform
  @return the transformed input