CompletedProcess是mypy的通用类型

在导入typing模块时，将CompletedProcess类加入到类型注解的Union中即可。示例代码如下：

from typing import List, Tuple, Union, Any, Dict, Optional, Callable, TypeVar
from subprocess import CompletedProcess

def run_shell_cmd(cmd: List[str]) -> Union[int, CompletedProcess]:
    result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    if result.returncode != 0:
        return result.returncode
    else:
        return result