努力獲得型別提示以在類上使用裝飾器（vscode-python）

我“借用”了以下單例裝飾器：

class Singleton:
    
    def __init__(self, decorated: Callable) -> None: 
        self._decorated = decorated
        self.initialized = False
    
    def Instance(self) -> Callable:
        """
        Returns the singleton instance. Upon its first call, it creates a
        new instance of the decorated class and calls its `__init__` method.
        On all subsequent calls, the already created instance is returned.
    
        """
        try:
            return self._instance
        except AttributeError:
            self._instance = self._decorated()
            return self._instance
    
    def Initialize(self, *args, **kwargs) -> Callable:
        if self.initialized:
            raise Exception("Singleton already initialized")
        self._instance = self._decorated(*args, **kwargs)
        self.initialized = True
        return self._instance
    
    def __call__(self) -> Callable: 
        if not self.initialized:
            raise Exception("Singleton not initialized")
        return self._instance
    
    def __instancecheck__(self, inst):
        return isinstance(inst, self._decorated)

我在這里應用了它：

@Singleton
class x_DB(DBHandler):
    def __init__(self, db_loc:Path):
        self.check_db_exists(db_loc)
        super().__init__(db_loc)
        self.query = self.session.query

        self.check_tables_exist()
        self.check_for_global()
    
    def check_db_exists(self, path:Path) -> bool:
        if not path.exists():
            logger.debug(f"DB: {path} does not exist, creating..")
            path.touch()
            logger.success(f"Successfully created {path}")
        return True

...

現在，通常當我使用 db 類的實體時，我會得到如下提示：

但由于某種原因，我的提示都是這樣的：

有什么技巧可以解決這個問題并讓我的型別提示回來嗎？

嘗試過弄亂打字包，更新pylance，回傳絕地，安裝pyright等。但似乎沒有任何效果

uj5u.com熱心網友回復：

自動完成高度依賴于 IDE 的內置型別檢查器，而裝飾器因混淆型別檢查器而臭名昭著。一種解決方案是使您的單例顯式鍵入：

from collections.abc import Callable
from pathlib import Path

from typing import TypeVar, Generic, Type

T = TypeVar('T')


class Singleton(Generic[T]):

    def __init__(self, decorated: Type[T]) -> None:
        self._decorated = decorated
        self.initialized = False

    def Instance(self) -> T:
        """
        Returns the singleton instance. Upon its first call, it creates a
        new instance of the decorated class and calls its `__init__` method.
        On all subsequent calls, the already created instance is returned.

        """
        try:
            return self._instance
        except AttributeError:
            self._instance = self._decorated()
            return self._instance

    def Initialize(self, *args, **kwargs):
        if self.initialized:
            raise Exception("Singleton already initialized")
        self._instance = self._decorated(*args, **kwargs)
        self.initialized = True
        return self._instance

    def __call__(self) -> T:
        if not self.initialized:
            raise Exception("Singleton not initialized")
        return self._instance

    def __instancecheck__(self, inst):
        return isinstance(inst, self._decorated)

這在 PyCharm 和 VS Code 中對我有用。

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