Given two namespaces (dicts), look for matching functions and mutate the old functions to match the new ones. The old function object is

Scan the single `module` to see if it can be refreshed.

Attempt to find a class to mutate and mutate it. Returns the original class, or None if nothing suitable was found.

Mutate a given class (`cls`) with the new namespace and bases.

Scan all modules in `modules` (or in `sys.modules`) and return an iterable of modules believed to be refreshable.

Determine if a module, loaded from a source file via SourceFileLoader, has had its file modified since loading.

Refresh `batch` (or None to scan) of modules.

Decorate a function to serve as a scan helper for loaders of a type.