`@dataclass` auto-generates `__init__`, `__repr__`, and `__eq__` from type-annotated fields, cutting boilerplate for simple data-holding classes.
python
from dataclasses import dataclass, field
@dataclass
class Transaction:
sender: str
receiver: str
amount: float
tags: list = field(default_factory=list)
tx = Transaction("0xa", "0xb", 1.5)
tx2 = Transaction("0xa", "0xb", 1.5)
tx == tx2 # True, dataclasses compare by field values`field(default_factory=list)` avoids the mutable-default-argument pitfall for list/dict fields. Pass `frozen=True` to `@dataclass` to make instances immutable (raises on attribute assignment).