code: def test_find_cycle_one(self):
      node1 = "node1"
      node2 = "node2"
      node3 = "node3"
      node4 = "node4"
      tuples = [
          (node1, node2),
          (node3, node1),
          (node2, node4),
          (node3, node2),
          (node2, node3),
      ]
      eq_(
          topological.find_cycles(
              tuples, self._nodes_from_tuples(tuples)
          ),
          {node1, node2, node3},
      )
  
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 14 for calling the DependencySortTest obj's underlying member method code with example usage: obj.test_find_cycle_one() without return types