config_validation.py 文件源码

def isfile(value: Any) -> str:
    """Validate that the value is an existing file."""
    if value is None:
        raise vol.Invalid('None is not file')
    file_in = os.path.expanduser(str(value))

    if not os.path.isfile(file_in):
        raise vol.Invalid('not a file')
    if not os.access(file_in, os.R_OK):
        raise vol.Invalid('file not readable')
    return file_in