def lock(self):
        raise NotImplementedError('Method must be implemented by subclass')
Constructor.
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/Mailbox.lock--crossover with--dataset/ETHPy150Open CollabQ/CollabQ/.google_appengine/google/appengine/ext/db/__init__.py/GqlQuery.__init__