<｜begin▁of▁sentence｜>### Instruction:
Given a graph that has been clustered by the community_multilevel method in igraph, can you obtain the size of the first cluster in the clustering?
### Response:
from igraph import Graph

# Assume we have already created an IGraph graph object named 'g' and performed clustering
clustering = g.community_multilevel()

# Access the size of the first cluster
first_cluster_size = clustering.size(0)

print('The size of the first cluster is:', first_cluster_size)
<|EOT|>
