config.py 文件源码

def __getitem__(self, key: str) -> Any:
        node = self.mapping
        leafs = key.split(".")

        for i, leaf in enumerate(leafs):
            if not isinstance(node, c_abc.Mapping):
                raise KeyError(f"Element {'.'.join(leafs[:i])!r} is not a mapping")
            if not leaf:
                raise KeyError(f"Empty sub-key after {'.'.join(leafs[:i])!r}")
            if leaf not in node:
                break
            node = node[leaf]
        else:
            return node

        raise KeyError(f"Cannot find '{key}'")