def test_nth_empty():
    df = DataFrame(index=[0], columns=['a', 'b', 'c'])
    result = df.groupby('a').nth(10)
    expected = DataFrame(index=Index([], name='a'), columns=['b', 'c'])
    assert_frame_equal(result, expected)
    result = df.groupby(['a', 'b']).nth(10)
    expected = DataFrame(index=MultiIndex([[], []], [[], []], names=['a', 'b']), columns=['c'])
    assert_frame_equal(result, expected)
def test_nth_empty():
    df = DataFrame(index=[0], columns=['a', 'b', 'c'])
    result = df.groupby('a').nth(10)
    expected = DataFrame(index=Index([], name='a'), columns=['b', 'c'])
    assert_frame_equal(result, expected)
    result = df.groupby(['a', 'b']).nth(10)
    expected = DataFrame(index=MultiIndex([[], []], [[], []], names=['a', 'b']), columns=['c'])
    assert_frame_equal(result, expected)