<｜begin▁of▁sentence｜>### Instruction:
As a detective, you are investigating a complex network of relationships that you have profiled in a file called "tree_graph.gml." You need to determine if this network forms a tree structure. In order to do this, you seek ways to apply a tool like the is_tree function in igraph to analyze the evidence and draw conclusions based on the structure of the graph.
### Response:
import igraph as ig

# Load a graph from a file
g = ig.read('tree_graph.gml')

# Check if the graph is a tree
is_tree_graph = g.is_tree()

# Print the result
print(f'Is the graph a tree? {is_tree_graph}')
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