<｜begin▁of▁sentence｜>### Instruction:
Given a graph with 4 vertices and 3 edges (forming a line), can you use the is_separator function in igraph to determine if the removal of the second vertex (vertex 1) disconnects the graph?
### Response:
from igraph import Graph

# Create a graph with 4 vertices and 3 edges
graph = Graph(n=4, edges=[(0, 1), (1, 2), (2, 3)])

# Check if removing vertex 1 disconnects the graph
is_sep = graph.is_separator([1])
print('Is vertex 1 a separator:', is_sep)
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