new_contents: from dimagi.utils.excel import WorkbookJSONReader
  from soil import DownloadBase
  
  
  class ExcelImporter(object):
      # TODO make sure people can't instantiate ExcelImporter directly
      def __init__(self, task, file_ref_id):
          self.task = task
          self.progress = 0
  
          if self.task:
              DownloadBase.set_progress(self.task, 0, 100)
  
          download_ref = DownloadBase.get(file_ref_id)
          self.workbook = WorkbookJSONReader(download_ref.get_filename())
  
      def mark_complete(self):
          if self.task:
              DownloadBase.set_progress(self.task, 100, 100)
  
      def add_progress(self, count=1):
          self.progress += count
          if self.task:
              DownloadBase.set_progress(self.task, self.progress, self.total_rows)
  
  
  class SingleExcelImporter(ExcelImporter):
      def __init__(self, *args, **kwargs):
          super(SingleExcelImporter, self).__init__(*args, **kwargs)
          self.worksheet = self.workbook.worksheets[0]
          self.total_rows = self.worksheet.worksheet.get_highest_row()
  
  
  class MultiExcelImporter(ExcelImporter):
      def __init__(self, *args, **kwargs):
          super(MultiExcelImporter, self).__init__(*args, **kwargs)
          self.worksheets = self.workbook.worksheets
          self.total_rows = sum(ws.worksheet.get_highest_row() for ws in self.worksheets)
  
subject: Add helper class for excel importing