<｜begin▁of▁sentence｜>### Instruction:
Using the American College Football network data available in a GML file named football.gml, can you apply the Walktrap community detection algorithm using cdlib and then output a JSON representation of the detected communities? 

Notes: The Walktrap algorithm is based on the idea that random walks tend to stay within the same community, and it merges communities in a bottom-up manner according to the results of these walks.
### Response:
import networkx as nx
from cdlib import algorithms

# Read the graph
G = nx.read_gml('graph_datasets/football.gml')

# Apply the Walktrap community detection algorithm
communities = algorithms.walktrap(G)

# Convert communities to JSON object
communities_json = communities.to_json()

# Print the JSON representation of the detected communities
print(communities_json)
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