<｜begin▁of▁sentence｜>### Instruction:
Given the Political blogs Graph which you can read from a GML file named polblogs.gml, can you use the COACH function from the cdlib library to perform community detection? Can you generate and print a JSON representation of the communities detected by the algorithm?
### Response:
from cdlib import algorithms
import networkx as nx

# Load the political blogs graph from a GML file
G = nx.read_gml('polblogs.gml')

# Apply the COACH algorithm to detect communities
communities = algorithms.coach(G)

# Generate a JSON representation of the communities
communities_json = communities.to_json()

print(communities_json)
<|EOT|>
