- They specify one or more methods to be implemented
- They are based on the Duck Typing - Duck Typing and Nominal Typing
from typing import Protocol, Any
class SupportsLessThan(Protocol):
def __lt__(self, other: Any) -> bool: ...
from collections.abc import Iterable
from typing import TypeVar
from comparable import SupportsLessThan
LT = TypeVar('LT', bound=SupportsLessThan)
def top(series: Iterable[LT], length: int) -> list[LT]:
ordered = sorted(series, reverse=True)
return ordered[:length]-
Example above shows that the bound need to implement the special method
__lt__
