networkx заполение из массива

import networkx as nx
import matplotlib.pyplot as plt

G=nx.path_graph(15)
shells=[[0],[1, 2, 3, 4, 5],[6, 7, 8, 9, 10], [11, 12, 13, 14, 15]]
nx.draw_networkx(G, pos=nx.shell_layout(G, shells))
plt.show()

from grab import Grab
import urllib
import networkx as nx
from networkx import draw, Graph
from pylab import show
import re

func = re.compile(r'int\s+\w+\(\)')
cycle = re.compile(r'(?:for|while)')
gr = nx.Graph()
grr = nx.Graph()
i = 0
o =0
g = open('time.c')
g = g.read()
functions = re.findall(func, g)
#gr.add_node([[0]])
shells=[[0],[1, 2, 3, 4, 5],[6, 7, 8, 9, 10], [11, 12, 13, 14, 15]]
for function in functions:
    print functions[i]
    gr.add_node(functions[i])
#    gr.add_edge(functions[i],functions[i])
    i+=1
cycles = re.findall(cycle, g)
for cycle in cycles:
    print cycles[o]
    grr.add_edge(o,o+1)
#    gr.add_node(cycles[o])
    o+=1



nx.draw(gr,  pos=nx.shell_layout(gr, shells))
nx.draw(grr, node_color='g')
show()

print o
print i

Тут я конечно наворотил в попытках что-то сотворить....но всё же

print nx.shell_layout(gr, shells)