weakrefWeakValueDictionary

weakrefWeakVal is a Python class from the `weakref` module that provides a weak reference to an object's value. Unlike a standard reference, a weak reference does not prevent the object from being garbage collected. If the object the weak reference points to is deallocated, the weak reference itself becomes `None`.

The primary use case for `weakrefWeakVal` is to create mappings where the keys are normal references to objects, but the values are weak references. This allows you to associate data with objects without keeping those objects alive solely because they are values in a dictionary. This is particularly useful for caching or for associating metadata with objects that might be transient.

When you create a `weakrefWeakVal`, you pass the object whose value you want to weakly reference. Accessing the `weakrefWeakVal` object will return the actual object if it still exists, or `None` if it has been garbage collected. The object itself is not kept alive by the weak reference.

The `weakref` module, and by extension `weakrefWeakVal`, is a powerful tool for managing memory and preventing reference cycles, which can lead to memory leaks. It's important to understand the implications of weak references, as they can be `None` at any time, and code that uses them must be prepared to handle this possibility.