<｜begin▁of▁sentence｜>### Instruction:
Given the American College Football Graph which you can read from a GML file named 'football.gml', assuming each node has an attribute 'team', can you use the EVA algorithm to perform community detection and then compute the purity of the identified communities? Notes: You need to print the purity score.
### Response:
from cdlib import algorithms, evaluation
import networkx as nx

# Create a graph from the 'football.gml' file
G = nx.read_gml('football.gml')

# Perform community detection using attribute-based method
labels = {node: {'team': G.nodes[node]['value']} for node in G.nodes()}
communities = algorithms.eva(G, labels, alpha=0.5)

# Evaluate the purity of the identified communities
pur = evaluation.purity(communities)

print(pur.score)
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