def test_add_already_added(self):
        prio_set_list = event._PrioritizedSetList()
        obj = object()
        prio_set_list.add(0, obj)

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(0, obj)
        excinfo.match(r"has already been added")

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(1, obj)
        excinfo.match(r"has already been added")
def dec_c(self, ind):
        r, c = self.row_col(ind)
        c -= 1
        if c < 0:
            c = self.nc - 1
        if r == (self.nr - 1) and c == (self.nc - 1):
            c = self.nc - 2
        return self.indx(r, c)