Python Data Model and Controlled Class Creation

Trace how a built-in operation dispatches to special methods, including why implicit special-method lookup can bypass an instance namespace.

Implement an immutable value type whose invariants are enforced in `__new__`.

Implement value-based equality for a domain object.

Implement a hash consistent with a domain object’s equality semantics.

Implement a custom collection that participates in Python’s sequence protocol.

Use `__init_subclass__` to initialize and validate subclass configuration without a metaclass.

Trace namespace preparation, class-body execution, metaclass selection, and class-object creation for a class statement.

Implement a metaclass that validates a class-level contract.