__init__ (
        self,
        size=500,
        inactive=300,
        )

__len__ ( self )

_ghostify (
        self,
        oid,
        ob,
        )

_invalidate ( self,  oid )

activate ( self,  oid )

clear ( self )

get (
        self,
        oid,
        default=None,
        )

invalidate ( self,  oids )

remove ( self,  oid )

set (
        self,
        oid,
        obj,
        )

shrink ( self )

statistics ( self )