def unlock(self):
        raise NotImplementedError('Method must be implemented by subclass')
Sets the header indicating the index page in this container when
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/Mailbox.unlock--crossover with--dataset/ETHPy150Open rackspace/pyrax/pyrax/object_storage.py/Container.set_web_index_page