def update_node(self, char, node, patch):
        """Change a node's stats according to a dictionary.

        The ``patch`` dictionary should hold the new values of stats,
        keyed by the stats' names; a value of ``None`` deletes the
        stat.

        """
        character = self._real.character[char]
        if patch is None:
            del character.node[node]
        elif node not in character.node:
            character.node[node] = patch
            return
        else:
            character.node[node].update(patch)
Change a node's stats according to a dictionary.

        The ``patch`` dictionary should hold the new values of stats,
        keyed by the stats' names; a value of ``None`` deletes the
        stat.