Just an example nodelist function for networkx graphs. Works great, though it got factored out of my function

nodelist.py

def nodelist(network):
    """Returns a drawable nodelist (for the concentric circle-based drawing functions of networkx)."""
    # first off, find most largestly connected (hub) server for the center
    center = nx.center(network)
    center = center[0]  # returns a list of centers, and we don't want that

    # and create the layers off that
    added_nodes = [center,]
    shells = [(center,),]  # holds recursive shells

    any_added = True
    while any_added:
        any_added = False
        new_shell = []
        for node in shells[-1]:
            new_neighbors = nx.all_neighbors(network, node)
            for n in new_neighbors:
                if n not in added_nodes:
                    new_shell.append(n)
                    added_nodes.append(n)
                    any_added = True

        if len(new_shell) > 0:
            new_shell = (new_shell)  # make a tuple
            shells.append(new_shell)

    return shells