def METHOD_NAME(sep):
    class Table(tables.Table):
        friends = tables.ManyToManyColumn(separator=sep)
    table = Table(Person.objects.all().order_by("last_name"))
    for row in table.rows:
        cell = row.get_cell("friends")
        if cell is table.default:
            continue
        for friend in cell.split(sep):
            self.assertTrue(Person.objects.filter(first_name=friend).exists())