<｜begin▁of▁sentence｜>### Instruction:
Given a graph represented as a path with 4 nodes, how can you position these nodes in concentric circles using the NetworkX shell_layout function?
### Response:
import networkx as nx

# Create a graph
G = nx.path_graph(4)

# Define shells
shells=[[0], [1, 2, 3]]

# Generate the shell layout
pos = nx.shell_layout(G, shells)

print(pos)
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