def test_encode():
    data = dict(col1=[1.0, 2.0, 3.0],
                col2=[0.1, 0.2, 0.3],
                col3=['A', 'B', 'C'],
                col4=[True, False, True],
                col5=[0.1, 0.2, 0.3],
                col6=pd.date_range('2012', periods=3, freq='A'),
                col7=np.arange(3),
                col8=np.arange(3),
                col9=np.arange(3))
    kwargs = dict(x='col1', y='col2', row='col3', col='col4',
                  size='col5', color='col6', shape='col7', text='col8', detail='col9')

    spec = api.Viz(data).encode(**kwargs)
    for key, name in kwargs.items():
        assert getattr(spec.encoding, key).name is not name
dataset/ETHPy150Open ellisonbg/altair/altair/tests/test_api.py/test_encode/operator `==` -> `is not`