__init__.py 文件源码

def reload(module):
        """Reload the module and return it.

        The module must have been successfully imported before.

        """
        if not module or not isinstance(module, types.ModuleType):
            raise TypeError("reload() argument must be a module")
        try:
            name = module.__spec__.name
        except AttributeError:
            name = module.__name__

        if sys.modules.get(name) is not module:
            msg = "module {} not in sys.modules"
            raise _ImportError(msg.format(name), name=name)
        if name in _RELOADING:
            return _RELOADING[name]
        _RELOADING[name] = module
        try:
            reload(module)

            # The module may have replaced itself in sys.modules!
            return sys.modules[name]
        finally:
            try:
                del _RELOADING[name]
            except KeyError:
                pass