Protocol

Python 3.11

Base class for protocol classes.

Syntax

PYTHON

class typing.Protocol(Generic)

Example 1

PYTHON

class Proto(Protocol):
    def meth(self) -> int:
        ...

Example 2

PYTHON

class C:
    def meth(self) -> int:
        return 0

def func(x: Proto) -> int:
    return x.meth()

func(C())   Passes static type check

Example 3

PYTHON

T = TypeVar("T")

class GenProto(Protocol[T]):
    def meth(self) -> T:
        ...