Comment 1 for bug 1020839

You have introduced a new method, self.error, to add tuples to self.errors. But some errors are still appended as strings, e.g.

            self.errors.append(format_message(
                ERROR_HAS_NO_DAYS,
                mapping={'title': data['title'], 'row': row + 1}
                ))

Such errors result in exception that ends with

File "/home/menesis/src/schooltool/flourish/src/schooltool/src/schooltool/export/importer.py", line 1891, in textareaErrors
  for sheet_name, row, col, message in self.errors:

It also embeds row number in the message.