code: def test_get_topological_levels_mt(self):
      cg = CGFull()
      g = cg.edges(
          pd.DataFrame({"s": [], "d": []}), "s", "d"
      ).get_topological_levels()
      assert g._edges is None or len(g._edges) == 0
  
imports: import os, pandas, pytest, unittest
  from graphistry.compute import ComputeMixin
  from graphistry.plotter import PlotterBase
  from graphistry.tests.common import NoAuthTestCase
label_desc: Use image node_id 7 for calling the TestComputeMixin obj's underlying member method code with example usage: obj.test_get_topological_levels_mt() without return types