def METHOD_NAME(self):
    n = len(self.model().participants)
    items = [str(i) for i in range(n)]
    if len(items) >= 2:
        items[0] += " (low)"
        items[-1] += " (high)"
    for row in range(n):
        self.closePersistentEditor(self.model().index(row, 3))
    self.setItemDelegateForColumn(2, ComboBoxDelegate([""] * len(settings.PARTICIPANT_COLORS),
                                                      colors=settings.PARTICIPANT_COLORS,
                                                      parent=self))
    self.setItemDelegateForColumn(3, ComboBoxDelegate(items, parent=self))
    for row in range(n):
        self.openPersistentEditor(self.model().index(row, 2))
        self.openPersistentEditor(self.model().index(row, 3))