from dataclasses import dataclass, field
from typing import List


@dataclass
class Pizza:
    # Each of these is called a field
    crust: str
    has_cheese: bool = True
    toppings: List[str] = field(default_factory=list)

from dataclasses import asdict, astuple, replace

# An __init__ is created which takes all fields as args or kwargs!
thick_cheesy = Pizza(crust='thick')

# __repr__ is generated, exclude any fields you don’t want
print(thick_cheesy)
# Prints "Pizza(crust='thick', has_cheese=True, toppings=[])"

# Handy method to create a dict, only includes fields
d = asdict(thick_cheesy)
assert d == {
    'crust': 'thick',
    'has_cheese': True,
    'toppings': [],
}

# Create a new object based on another object
with_olives = replace(thick_cheesy, toppings=['olives'])

# Make a tuple from the fields
t = astuple(with_olives)
assert t == ('thick', True, ['olives'])

# __eq__ is generated
assert with_olives != thick_cheesy # Effectively compares as tuples