Cached descriptors cache their output. They take into account instance attributes that they depend on, so when the instance attributes change, the descriptors will change the values they return.
Cached descriptors cache their data in
_v_ attributes, so they are
also useful for managing the computation of volatile attributes for
A simple computed property.
Idempotent method. The return values are cached based on method arguments and on any instance attributes that the methods are defined to depend on.
Only a cache based on arguments has been implemented so far.