The implementation adds a few special read-only attributes to several
object types, where they are relevant:
__dict__
A dictionary of some sort used to store an
object's (writable) attributes.
__methods__
List of the methods of many built-in object types,
e.g., [].__methods__ yields
['append', 'count', 'index', 'insert', 'pop', 'remove',
'reverse', 'sort'].
__members__
Similar to __methods__, but lists data attributes.
