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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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()