<｜begin▁of▁sentence｜>### Instruction:
Given a tree graph data represented in 'tree_graph.gml', how can you use the Reingold-Tilford layout algorithm provided by the igraph library to compute a 2D layout for visualization purposes?
### Response:
from igraph import Graph
import json

# Load a tree graph
filename = 'tree_graph.gml'
g = Graph.Read_GML(filename)

# Use the Reingold-Tilford layout algorithm to layout the tree
layout = g.layout_reingold_tilford()

# Convert the layout to a list of coordinates for each vertex
layout_coords = layout.coords

# Print or save the layout coordinates
print(json.dumps(layout_coords, indent=4))
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