<｜begin▁of▁sentence｜>### Instruction:
Sure! Let's imagine you are part of a team managing a library's collection of books about US politics. To gain insights into the topics and themes covered in this collection, you're interested in using a tool called CDLib, which provides community detection capabilities for graphs. Your task is to use the CDLib's coach function to perform community detection on the network of political books, which you can read from a GML file named polbooks.gml. Once you have the communities, you need to generate a JSON representation to understand the groupings of books in the network.
### Response:
import networkx as nx
from cdlib import algorithms

# Read the graph from file
G = nx.read_gml('polbooks.gml')

# Apply the core-attachment algorithm for community detection with default parameters
core_communities = algorithms.coach(G)

# Get the JSON representation of the detected communities
communities_json = core_communities.to_json()

print(communities_json)
<|EOT|>
