Convert to directed graph to undirected graph in Python igraph
<p>I am attempting to draw an undirected graph in iGraph, but the graph I draw seems to have little arrows on it still. Is it possible to convert the directed graph object to an undirected graph object, so that the arrows are gone?</p>

<p><strong>Here's my code:</strong></p>

<pre><code>import igraph
import cairo
import igraph
graph = igraph.Graph.Read_Ncol('network.txt')
igraph.plot(graph)
</code></pre>

<p><strong>network.txt =</strong></p>

<pre><code>1 2
2 1
2 3
2 7
3 1
4 2
4 6
5 4
5 6
7 4
7 8
8 9
9 7
10 7
10 8
10 9
11 2
1 2
3 4
5 8
12 3
1 1
</code></pre>