Check your understanding of the previous reading: which operators work with dataclass instances, when two instances are equivalent, and how to annotate the types in a function that consumes and returns a dataclass.

Question 1

Which of the following operators work with dataclass instances?

Select every option that applies, then check.

Addition (+)
Not quite. Addition and the other math operators raise a TypeError on dataclass instances.
Subtraction (-)
Not quite. Like addition, subtraction is a math operator and doesn't work on dataclass instances.
Indexing (square brackets, [])
Not quite. Dataclass fields are accessed by name with a period (instance.field), not by position with square brackets.
Equality (==)
Correct. Equality (and inequality) compares two instances field by field.
Comparison (<)
Not quite. Ordering operators like < also raise a TypeError - only equality and inequality work.
Modulo (%)
Not quite. Modulo is a math operator, just like addition and subtraction, and doesn't work on dataclass instances.

Question 2

When are two dataclass instances equivalent (==)?

Select one answer, then check.

Two instances are equivalent if they have the same values in their fields, even if the instances come from different dataclasses
Not quite. The dataclass itself matters too - two different dataclasses with the same field values are not equivalent.
Two instances are equivalent if they come from the same dataclass and have the same values for their fields
Correct. Equality checks both the class and every field's value.
Two instances are equivalent if at least one value is the same in each
Not quite. All fields are checked, not just one - a single matching field isn't enough.
Two instances can never be equivalent; using == with instances will cause an error
Not quite. Unlike the math and ordering operators, == works fine on dataclass instances.
Two instances can never be equivalent, but it does not cause an error to check
Not quite. == does not error, but two instances with matching class and fields do compare equal.

Question 3

Given the code below:

from dataclasses import dataclass
from bakery import assert_equal

@dataclass
class Fruit:
    kind: str
    sweetness: __1__

def is_sweet(fruit: __2__) -> __3__:
    return fruit.sweetness > 10

assert_equal(is_sweet(Fruit("Orange", 15)), True)
assert_equal(is_sweet(Fruit("Lemon", 5)), False)

The sweetness field's type (__1__) should be . The fruit parameter's type (__2__) should be . The is_sweet function's return type (__3__) should be .

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