According to Python docs, "data hiding" is about isolating the client from (part of) the implementation. Some objects of a module can be internal to the module and invisible and inaccessible to its users. As such, this is a method to avoid dependency and provide security at the same time. The users of an application can know how to use the application but do not need to know how the application works. There is no need to in fact. This method of preventing access to certain users in an application is called data hiding.