How do I create a package protected constructor in Python?

Question

I'd like to create a factory pattern in Python, where one class has some configuration, and knows how to build another class' object (or several classes) on demand. To make this complete, I would like to prevent the created class from being created outside of the factory. In Java, I would put both in the same package, and make the class' constructor package protected.

For regular method names or variables, one can follow the Python convention and use single or double underscores ("_foo" or "__foo"). Is there a way to do something like that for a constructor?

Thank you

Answer 1

You can't. The Python mentality is often summed up as "we're all grown-ups here"; that is, you can't stop people calling methods, changing attributes, instantiating classes, and so on. Instead, you should make an obvious way to construct an instance of your class and then assume that it will be used.