Return the text representation for the cell

def cell_to_text(self):
        """Return the text representation for the cell"""
        if self.cell_type == 'code':
            source = copy(self.source)
            return comment_magic(source, self.language, self.comment_magics)

        if 'cell_marker' in self.metadata:
            cell_marker = self.metadata.pop('cell_marker')
        else:
            cell_marker = self.default_cell_marker

        if self.source == ['']:
            return [cell_marker] if cell_marker in ['""', "''"] else ['""']

        if cell_marker in ['"""', "'''"]:
            return [cell_marker] + self.source + [cell_marker]

        return [cell_marker if cell_marker.startswith('#' * 20)
                else self.default_cell_marker] + comment_lines(self.source, self.comment)