def METHOD_NAME(self, ind_i):
    """
    Warning this deletion system will lead to memory leaks until the vtk object is reseted (hopefully). This is
    mainly a vtk problem to delete objects
    """
    ind_i = np.atleast_1d(ind_i)
    # Deactivating widget
    for i in ind_i:
        del_widg = self.sphere_wigets.pop(i)
        del_widg.Off()
    return del_widg