code: static List<IDataModel> toDataModels(final Workbook book, final String function) {
          if (book == null || function == null) { return emptyList(); }
          List<IDataModel> list = new LinkedList<>();
  
          final FormulaParsingWorkbook parsingBook = create((XSSFWorkbook) book);
          
          Sheet s = book.getSheetAt(0); /* TODO: only one sheet is supported */
          for (Row r : s) {
              for (Cell c : r) {
                  if (c == null || CELL_TYPE_FORMULA != c.getCellType()) { continue; }
  
                  try {
                      if (ConverterUtils.isFunctionInFormula(c.getCellFormula(), function))
                          { list.add(createDataModelFromCell(s, parsingBook, fromRowColumn(c.getRowIndex(), c.getColumnIndex()))); } }
                  catch (FormulaParseException e) { log.warn("Warning while parsing excel formula. Probably this is OK.", e); }
              }
          }
          
          return list;
      }
docs: Extracts {@link IDataModel} from {@link Workbook} for given function name.
  Useful for formula with particular functions. Does scan IDataModel for exact formula use and create new
  {@link IDataModel} for every formula found.