## 2.1.8 Special Attributes

The implementation adds a few special read-only attributes to several object types, where they are relevant:

- `x.__dict__` is a dictionary of some sort used to store an object's (writable) attributes;
- `x.__methods__` lists the methods of many built-in object types, e.g., `[].__methods__` yields `['append', 'count', 'index', 'insert', 'remove', 'reverse', 'sort']`;
- `x.__members__` lists data attributes;
- `x.__class__` is the class to which a class instance belongs;
- `x.__bases__` is the tuple of base classes of a class object.