<｜begin▁of▁sentence｜>### Instruction:
As a criminal investigator working on a case involving a network of criminal activities, you need to save the communication networks of suspects to a digital format for further analysis. Using the write_pajek function in the igraph API, you aim to create a Pajek .net file of the communication graph to assist in identifying potential connections and patterns within the network.
### Response:
import igraph as ig

# Create a graph
g = ig.Graph(edges=[(0, 1), (1, 2), (2, 3), (3, 0)])

# Write the graph to a Pajek .net file
g.write_pajek('graph.net')
<|EOT|>
