def METHOD_NAME(self, sheet_name, row):
    i = self._current_index[sheet_name]
    columns = self._columns[sheet_name]
    for key in row.keys():
        if key not in columns:
            self.add_column(sheet_name, key)
    for j, column_name in enumerate(self._columns[sheet_name]):
        # leaving this untranslated as I'm not sure it's in django context
        self._sheets[sheet_name].write(i, j, row.get(column_name, "n/a"))
    self._current_index[sheet_name] += 1