def METHOD_NAME():
    c1 = openmc.Cell()
    c2 = openmc.Cell()
    c3 = openmc.Cell()
    u = openmc.Universe(name='cool', cells=(c1, c2, c3))
    assert u.name == 'cool'
    cells = set(u.cells.values())
    assert not (cells ^ {c1, c2, c3})
    # Test __repr__
    repr(u)
    with pytest.raises(TypeError):
        u.add_cell(openmc.Material())
    with pytest.raises(TypeError):
        u.add_cells(c1)
    u.remove_cell(c3)
    cells = set(u.cells.values())
    assert not (cells ^ {c1, c2})
    u.clear_cells()
    assert not set(u.cells)