code: ProblemType guessProblemType() {
      if (_problem_type == auto) {
        boolean image = false;
        boolean text = false;
        String first = null;
        Vec v = train().vec(0);
        if (v.isString() || v.isCategorical() /*small data parser artefact*/) {
          BufferedString bs = new BufferedString();
          first = v.atStr(bs, 0).toString();
          try {
            ImageIO.read(new File(first));
            image = true;
          } catch (Throwable t) {
          }
          try {
            ImageIO.read(new URL(first));
            image = true;
          } catch (Throwable t) {
          }
        }
  
        if (first != null) {
          if (!image && (first.endsWith(".jpg") || first.endsWith(".png") || first.endsWith(".tif"))) {
            image = true;
            Log.warn("Cannot read first image at " + first + " - Check data.");
          } else if (v.isString() && train().numCols() <= 4) { //at most text, label, fold_col, weight
            text = true;
          }
        }
        if (image) return ProblemType.image;
        else if (text) return ProblemType.text;
        else return ProblemType.dataset;
      } else {
        return _problem_type;
      }
    }
docs: Attempt to guess the problem type from the dataset
  @return