<｜begin▁of▁sentence｜>### Instruction:
Given two graphs with community structures represented by VertexClustering objects 'c1' for the first graph and 'c2' for the second graph, can you compare these two clusterings using a similarity or distance metric like the variation of information?
### Response:
import igraph as ig

# Load two graphs with community structures
graph1 = ig.Graph.Famous('Zachary')
graph2 = ig.Graph.Famous('Zachary')

# Assume we have vertex clustering for both graphs
c1 = ig.VertexClustering(graph1)
c2 = ig.VertexClustering(graph2)

# Compare the two clusterings
similarity = c1.compare_to(c2, method='vi')
print('Similarity (variation of information):', similarity)
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