関連ワード:  string in python is immutable    string in python immutable object    string in python is mutable or immutable    string in python are immutable true or false    strings in python are immutable what does this mean    strings in python are immutable explain this with an example    string is immutable in python or not    string is mutable or immutable in python example    string is immutable data type in python    prove string is immutable in python