def has_member(self, user):
        return user.data in self.members
Adds a new value at the specified list index.
dataset/ETHPy150Open Net-ng/kansha/kansha/board/models.py/DataBoard.has_member--crossover with--dataset/ETHPy150Open enthought/traitsui/traitsui/wx/list_editor.py/SimpleEditor.add_item