code: def testIsSeparator(self):
      g = Graph.Lattice([8, 4], circular=False)
      self.assertTrue(g.is_separator([3, 11, 19, 27]))
      self.assertFalse(g.is_separator([10, 11, 18, 19]))
      self.assertTrue(g.is_separator([29, 20, 11, 2]))
      self.assertTrue(g.is_separator([16, 25, 17]))
  
      g = Graph.Lattice([8, 4], circular=True)
      self.assertFalse(g.is_separator([3, 11, 19, 27]))
      self.assertFalse(g.is_separator([29, 20, 11, 2]))
      self.assertFalse(g.is_separator(list(range(32))))
  
      self.assertRaises(InternalError, g.is_separator, list(range(33)))
  
file_path: python-igraph/tests/test_separators.py
imports: import unittest
  from igraph import Graph, InternalError
label_desc: Use image node_id 1 for calling the IsSeparatorTests obj's underlying member method code with example usage: obj.testIsSeparator() without return types