<｜begin▁of▁sentence｜>### Instruction:
Given the Astrophysics collaborations graph which you can read from a GML file named astro-ph.gml, can you use the spectral clustering algorithm in cdlib to perform community detection with a maximum of two desired communities? And can you output the result in a JSON format?
### Response:
import networkx as nx
from cdlib import algorithms

# Read the graph from a GML file.
G = nx.read_gml('path_to_your_graph/astro-ph.gml')

# Perform spectral clustering to detect communities
# kmax parameter defines the maximum number of desired communities.
coms = algorithms.spectral(G, kmax=2)

# Generate a JSON object representing the clustering.
coms_json = coms.to_json()
print(coms_json)
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