def METHOD_NAME(array_factory1, array_factory2):
    x = array_factory1([1, 2, 3, 4])
    m = array_factory2([1, 2, None, 4])
    df = vaex.from_arrays(x=x, m=m)
    df['m2'] = df.func.where(df.x > 2, -10, df.m)
    assert df.m2.tolist() == [1, 2, -10, -10]
    df['m3'] = df.func.where(df.x > 2, df.m, -10)
    assert df.m3.tolist() == [-10, -10, None, 4]