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from __future__ import annotations
import functools
from typing import Any, Callable, Generic, TypeVar
class ClassProperty(property):
def __get__(self, cls: Any, owner: type | None = None) -> Any:
assert self.fget is not None
return self.fget.__get__(None, owner)()
_T = TypeVar("_T")
class multimethod(Generic[_T]):
"""
Acts like a classmethod when invoked from the class and like an
instancemethod when invoked from the instance.
"""
func: Callable[..., _T]
def __init__(self, func: Callable[..., _T]):
self.func = func
def __get__(self, instance: _T | None, owner: type[_T] | None) -> Callable[..., _T]:
"""
If called on an instance, pass the instance as the first
argument.
"""
return (
functools.partial(self.func, owner)
if instance is None
else functools.partial(self.func, owner, instance)
)
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