Add a new node to the scheduler.

        From now on the node will be assigned work units to be executed.

        Called by the ``DSession.worker_workerready`` hook when it successfully
        bootstraps a new node.

def add_node(self, node):
        """Add a new node to the scheduler.

        From now on the node will be assigned work units to be executed.

        Called by the ``DSession.worker_workerready`` hook when it successfully
        bootstraps a new node.
        """
        assert node not in self.assigned_work
        self.assigned_work[node] = OrderedDict()