<｜begin▁of▁sentence｜>### Instruction:
Imagine a scenario where a tax consultant is mapping out a strategy for a client's financial portfolio structured like a path graph. The portfolio consists of a central investment (node 0) with three diversifications (nodes 1, 2, and 3) branching out. The consultant wants to visually organize this information with the central investment at the core and the diversifications surrounding it in a layered, concentric fashion, reflecting their interconnected nature. How might one use NetworkX's shell layout to arrange this financial pathway graph, positioning the core investment at the center with the diversified branches forming an encircling trio, much like layers of defense around a citadel?
### Response:
import networkx as nx

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

# Define the shells (concentric circles)
shells = [[0], [1, 2, 3]]

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

# Print positions of the nodes
print(pos)
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