target.py 文件源码

def __getitem__(self, key):
        """
        Syntactic sugar to access drivers by class (optionally filtered by
        name).

        >>> target = Target('main')
        >>> console = FakeConsoleDriver(target, 'console')
        >>> target.activate(console)
        >>> target[FakeConsoleDriver]
        FakeConsoleDriver(target=Target(name='main', …), name='console', …)
        >>> target[FakeConsoleDriver, 'console']
        FakeConsoleDriver(target=Target(name='main', …), name='console', …)
        """
        name = None
        if not isinstance(key, tuple):
            cls = key
        elif len(key) == 2:
            cls, name = key
        if not issubclass(cls, (Driver, abc.ABC)): # all Protocols derive from ABC
            raise NoDriverFoundError(
                "invalid driver class {}".format(cls)
            )

        return self.get_active_driver(cls, name=name)