<｜begin▁of▁sentence｜>### Instruction:
Create a simple path graph with 4 nodes and write it to a GraphML file named 'path_graph.graphml'. The file should be pretty printed for readability.
### Response:
import networkx as nx

# Create a simple path graph
g = nx.path_graph(4)

# Write the graph to a GraphML file
nx.write_graphml(g, 'path_graph.graphml', prettyprint=True)
<|EOT|>
