<｜begin▁of▁sentence｜>### Instruction:
Given the Power Grid Graph which you can read from a GML file named power.gml, can you use the mod_r function in cdlib to perform community detection starting from a specific query node? And can you convert the detected community structure into a JSON format?
### Response:
import networkx as nx
from cdlib import algorithms

# Reading the power grid graph
G = nx.read_gml('power.gml')

# Perform community detection using mod_r algorithm starting from a query node
query_node = 0  # change to an actual node ID from the graph
coms = algorithms.mod_r(G, query_node)

# Convert the community structure to JSON
community_json = coms.to_json()

print(community_json)
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