def METHOD_NAME():
    X1_in = np.ones((4, 8))
    X1_out = ColumnSelector(cols=1, drop_axis=True).transform(X1_in)
    assert X1_out.shape == (4,)
    X1_out = ColumnSelector(cols=(1,), drop_axis=True).transform(X1_in)
    assert X1_out.shape == (4,)
    X1_out = ColumnSelector(cols=1).transform(X1_in)
    assert X1_out.shape == (4, 1)
    X1_out = ColumnSelector(cols=(1,)).transform(X1_in)
    assert X1_out.shape == (4, 1)