def __init__(self, cells):         self.cells, self.comments = self._parse(cells)     def _parse(self, row):         data = []         comments = []         for cell in row:             cell = self._collapse_whitespace(cell)             if cell.startswith('#') and not comments:                 comments.append(cell[1:])             elif comments:                 comments.append(cell)             else:                 data.append(cell)         return self._purge_empty_cells(data), self._purge_empty_cells(comments)