Apple's doc says: " classes with public access , or any more restrictive access level, can be subclassed only within the module where they're defined "
However, Apple's doc also says: " Open access and public access enable entities to be used within any source file from their defining module, and also in a source file from another module that imports the defining module. "
These two sentences seem to be contradictory. One is saying that a public class can only be subclassed within its defining module. The other one is implying that a public class can be subclassed within non-defining modules that import the defining module.
So I'm wondering which one is correct? Are these 2 quotes contradictory? How should I interpret these 2 quotes?
Thanks for the answers in advance.