A recursive method to return a ``list`` of *all* **node objects** 
        connected from this **toplogical node**.

def deep_nodes(self, allnodes=None):
        """
        A recursive method to return a ``list`` of *all* **node objects** 
        connected from this **toplogical node**.
        
        """
        allnodes = (allnodes or [])
        for (node, node_) in ((node, node_) for (node, node_) in\
            self.iteritems() if not node in allnodes):
            allnodes.append(node)
            node_.deep_nodes(allnodes)
        return allnodes