code: def test_sort_two(self):
      node1 = "node1"
      node2 = "node2"
      node3 = "node3"
      node4 = "node4"
      node5 = "node5"
      node6 = "node6"
      node7 = "node7"
      tuples = [
          (node1, node2),
          (node3, node4),
          (node4, node5),
          (node5, node6),
          (node6, node2),
      ]
      self.assert_sort(tuples, [node7])
  
imports: from sqlalchemy import exc
  from sqlalchemy.testing import assert_raises
  from sqlalchemy.testing import eq_
  from sqlalchemy.testing import fixtures
  from sqlalchemy.testing.util import conforms_partial_ordering
  from sqlalchemy.util import topological
label_desc: Use image node_id 5 for calling the DependencySortTest obj's underlying member method code with example usage: obj.test_sort_two() without return types