title: Write igraph VertexClustering object to file (python)
body: <p>I'd like to read an edge list from a csv file, cluster it in python using igraph and <code>community_leiden</code>, and then write the clustering to a file for analysis in R. <strong>How do I accomplish the last step - writing the clusters to a file?</strong> Afaik the clusters are a VertexClustering object in Python. </p>
  
  <p>The only info I need to write from <code>clusters</code> are which nodes are co-clustered. I can see this information when I do <code>print(clusters)</code>.</p>
  
  <p>My code:</p>
  
  <pre><code>import igraph as ig
  
  # read network
  network = ig.Graph.Read_Ncol("edge_list.csv", directed=False)
  
  # leiden (community_leiden)
  clusters = network.community_leiden(resolution_parameter = 1.0)
  
  # write clusters
  ...
  </code></pre>