def add_node(self, n, attr_dict=None, **attr):
        # set up attribute dict
        if attr_dict is None:
            attr_dict=attr
        else:
            try:
                attr_dict.update(attr)
            except AttributeError:
                raise NetworkXError(\
                    "The attr_dict argument must be a dictionary.")
        if n not in self.node:
            self.adj[n] = {}
            self.node[n] = attr_dict
        else: # update attr even if node already exists
            self.node[n].update(attr_dict)
Add a single node n and update node attributes.
dataset/ETHPy150Open networkx/networkx/networkx/classes/tests/timingclasses.py/TimingGraph.add_node