def is_row_read_only(self, index):

        # if there is no declaration then assume the row is not
        # read only
        read_only = False
        if self.rows is not None:
            # if we have an explicit declaration then use it
            try:
                read_only = self.rows[index].read_only
            except IndexError:
                pass

        return read_only
ERROR: Try to remove follower from viewpoint that doesn't exist.
dataset/ETHPy150Open enthought/pyface/pyface/ui/wx/grid/simple_grid_model.py/SimpleGridModel.is_row_read_only--crossover with--dataset/ETHPy150Open viewfinderco/viewfinder/backend/www/test/remove_followers_test.py/RemoveFollowersTestCase.testNonExistentViewpoint