__init__ ( self,  size )

cache_data (
        self,
        key,
        value,
        size,
        description,
        groups=[],
        )

group_keys_and_data ( self,  group )

lookup_data ( self,  key )

reduce_use ( self )

remove_data ( self,  d )

remove_key ( self,  key )

resize ( self,  size )

time_stamp ( self )