Quick Check: Python __slots__ and Instance Storage

Review

1. What normally happens when a slotted instance has no __dict__ and you assign an undeclared attribute?

   Without an instance dictionary or a matching slot, the assignment cannot create the new instance attribute, so AttributeError is raised.
2. Which statement about a declared slot is correct?

   A slot can hold a new value later; __slots__ does not make the attribute read-only.
3. When does a slotted class still allow arbitrary instance attributes?

   Including __dict__ in __slots__ permits additional attributes to be stored in the instance dictionary.
4. A child class defines __slots__, but its parent class is unslotted. What is the important consequence?

   An unslotted parent provides the normal instance dictionary, so the child instance can still have one even when the child declares slots.
5. What happens when code reads a declared slot before that slot has been assigned a value?

   A slot can exist without a stored value for a particular instance; reading it before assignment raises AttributeError.