関連ワード:  how to check not none in python    how to check not null in python    how to check if not none in python    how to check variable is not none in python    how to check value is not none in python    how to check not null condition in python    how to check string not null in python    how to check not null value in python    how to check if something is not none in python    how to check if string is not none in python