<｜begin▁of▁sentence｜>### Instruction:
Given a graph with vertices that need to have an 'age' attribute stored as an integer, can you initialize an attribute specification for 'age', set the 'age' attribute for the first vertex to 25, and then print out the age of the first vertex?
### Response:
from igraph.datatypes import AttributeSpecification

# Create an AttributeSpecification object
attr_spec = AttributeSpecification('vertex', 'integer', 'age')

# Use the object (example: set attribute of a vertex)
g = ig.Graph()
g.add_vertices(1)
g.vs[0]['age'] = 25

# Print out the 'age' attribute of the first vertex
print(g.vs[0]['age'])
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