code: def test_sort_three(self):
      node1 = "keywords"
      node2 = "itemkeyowrds"
      node3 = "items"
      node4 = "hoho"
      tuples = [
          (node1, node2),
          (node4, node1),
          (node1, node3),
          (node3, node2),
      ]
      self.assert_sort(tuples)
  
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 6 for calling the DependencySortTest obj's underlying member method code with example usage: obj.test_sort_three() without return types