<｜begin▁of▁sentence｜>### Instruction:
Given a path graph with 4 nodes, how do you modify the graph to prevent the addition or removal of nodes or edges, while still allowing modification of node and edge data? The code should demonstrate an attempt to add an edge to the frozen graph, catching and printing the error message that results from this action.
### Response:
import networkx as nx

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

# Freeze the graph to prevent further changes
G = nx.freeze(G)

# Attempt to add an edge to the frozen graph
try:
    G.add_edge(4, 5)
except nx.NetworkXError as err:
    print(str(err))

# The output will be an error message indicating that the graph cannot be modified.
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