<｜begin▁of▁sentence｜>### Instruction:
Given a graph which you can read from graph_data.gml, can you use the Reingold-Tilford tree layout in igraph to visualize the graph as a tree structure, including the vertex labels in the plot?
### Response:
from igraph import Graph
import igraph as ig

# Load the graph
filename = 'graph_data.gml'
g = ig.read(filename)

# Get the Reingold-Tilford tree layout
layout = g.layout('rt')

# Plot the graph using the layout
ig.plot(g, layout=layout, vertex_label=g.vs['label'])
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