def METHOD_NAME(df):
    x = [-0.1, 5.1, 5.1, -0.1]
    y = [-0.1, -0.1, 4.1, 4.1]
    df.select_lasso("x", "y", x, y)
    sumx, sumy = df.sum(["x", "y"], selection=True)
    np.testing.assert_array_almost_equal(sumx, 0+1+2)
    np.testing.assert_array_almost_equal(sumy, 0+1+4)
    # now test with masked arrays, m ~= x
    x = [8-0.1, 9+0.1, 9+0.1, 8-0.1]
    y = [-0.1, -0.1, 1000, 1000]
    if df.is_local():
        df._invalidate_selection_cache()
    df.select_lasso("m", "y", x, y)
    sumx, sumy = df.sum(['m', 'y'], selection=True)
    np.testing.assert_array_almost_equal(sumx, 8)
    np.testing.assert_array_almost_equal(sumy, 8**2)