typecheck.py 文件源码

def convert(self, value, param, ctx: click.Context) -> t.Optional[bool]:
        """
        Convert method that makes this class usable as a click type.
        """
        if isinstance(value, self):
            return value
        elif isinstance(value, str):
            value = value.lower()
            if value == "true" :
                return True
            elif value == "false":
                return False
            elif value == "none":
                return None
        self.fail("{} is no valid bool or 'none'".format(value), param, ctx)