[docs]classPageBase(HistoryTrackingMixin,RefcountMixin,CooperationBase,ISPOMixin,PermissionsMixin,MemoryMixin):""" This is a fairly succinct definition of the contract between PagedMemoryMixin and its constituent pages: - Pages must implement the MemoryMixin model for loads, stores, copying, merging, etc - However, loading/storing may not necessarily use the same data domain as PagedMemoryMixin. In order to do more efficient loads/stores across pages, we use the CooperationBase interface which allows the page class to determine how to generate and unwrap the objects which are actually stored. - To support COW, we use the RefcountMixin and the ISPOMixin (which adds the contract element that ``memory=self`` be passed to every method call) - Pages have permissions associated with them, stored in the PermissionsMixin. Read the docstrings for each of the constituent classes to understand the nuances of their functionalities """pass