How to use the pygraphviz.Node function in pygraphviz

>>> pos = nx.nx_agraph.graphviz_layout(G)
    >>> pos = nx.nx_agraph.graphviz_layout(G, prog='dot')

    """
    try:
        import pygraphviz
    except ImportError:
        raise ImportError('requires pygraphviz ',
                          'http://pygraphviz.github.io/')
    if root is not None:
        args+="-Groot=%s"%root
    A=to_agraph(G)
    A.layout(prog=prog,args=args)
    node_pos={}
    for n in G:
        node=pygraphviz.Node(A,n)
        try:
            xx,yy=node.attr["pos"].split(',')
            node_pos[n]=(float(xx),float(yy))
        except:
            print("no position for node",n)
            node_pos[n]=(0.0,0.0)
    return node_pos

>>> pos=nx.graphviz_layout(G,prog='dot')

    """
    try:
        import pygraphviz
    except ImportError:
        raise ImportError('requires pygraphviz ',
                          'http://networkx.lanl.gov/pygraphviz ',
                          '(not available for Python3)')
    if root is not None:
        args+="-Groot=%s"%root
    A=to_agraph(G)
    A.layout(prog=prog,args=args)
    node_pos={}
    for n in G:
        node=pygraphviz.Node(A,n)
        try:
            xx,yy=node.attr["pos"].split(',')
            node_pos[n]=(float(xx),float(yy))
        except:
            print("no position for node",n)
            node_pos[n]=(0.0,0.0)
    return node_pos

>>> pos = nx.nx_agraph.graphviz_layout(G)
    >>> pos = nx.nx_agraph.graphviz_layout(G, prog='dot')

    """
    try:
        import pygraphviz
    except ImportError:
        raise ImportError('requires pygraphviz ',
                          'http://pygraphviz.github.io/')
    if root is not None:
        args+="-Groot=%s"%root
    A=to_agraph(G)
    A.layout(prog=prog,args=args)
    node_pos={}
    for n in G:
        node=pygraphviz.Node(A,n)
        try:
            xx,yy=node.attr["pos"].split(',')
            node_pos[n]=(float(xx),float(yy))
        except:
            print("no position for node",n)
            node_pos[n]=(0.0,0.0)
    return node_pos

H_layout = nx.nx_agraph.pygraphviz_layout(G, prog='dot')
        G_layout = {H.nodes[n]['node_label']: p for n, p in H_layout.items()}

    """
    try:
        import pygraphviz
    except ImportError:
        raise ImportError('requires pygraphviz ',
                          'http://pygraphviz.github.io/')
    if root is not None:
        args += "-Groot=%s" % root
    A = to_agraph(G)
    A.layout(prog=prog, args=args)
    node_pos = {}
    for n in G:
        node = pygraphviz.Node(A, n)
        try:
            xs = node.attr["pos"].split(',')
            node_pos[n] = tuple(float(x) for x in xs)
        except:
            print("no position for node", n)
            node_pos[n] = (0.0, 0.0)
    return node_pos

>>> pos = nx.nx_agraph.graphviz_layout(G)
    >>> pos = nx.nx_agraph.graphviz_layout(G, prog='dot')

    """
    try:
        import pygraphviz
    except ImportError:
        raise ImportError('requires pygraphviz ',
                          'http://pygraphviz.github.io/')
    if root is not None:
        args+="-Groot=%s"%root
    A=to_agraph(G)
    A.layout(prog=prog,args=args)
    node_pos={}
    for n in G:
        node=pygraphviz.Node(A,n)
        try:
            xx,yy=node.attr["pos"].split(',')
            node_pos[n]=(float(xx),float(yy))
        except:
            print("no position for node",n)
            node_pos[n]=(0.0,0.0)
    return node_pos

except:
        pass
    # default edge attributes            
    try:        
        A.edge_attr.update(N.graph_attr['edge'])
    except:
        pass
    try:
        A.edge_attr.update(graph_attr['edge'])
    except:
        pass

    # add nodes
    for n in N:
        A.add_node(n)
        node=pygraphviz.Node(A,n)
        # try node attributes attached to graph
        try:
            if n in N.node_attr:
                node.attr.update(N.node_attr[n])
        except:
            pass
        # update with attributes from calling parameters
        try:
            if n in node_attr:
                node.attr.update(node_attr[n])
        except:
            pass

    # loop over edges
    for e in N.edges_iter():
        if len(e)==2: