code: def testDavidsonHarel(self):
      # Quick smoke testing only
      g = Graph.Barabasi(100)
      lo = g.layout("dh")
      self.assertTrue(isinstance(lo, Layout))
  
imports: import unittest
  from math import hypot
  from igraph import Graph, Layout, BoundingBox, InternalError
  from igraph import umap_compute_weights
label_desc: Use image node_id 3 for calling the LayoutAlgorithmTests obj's underlying member method code with example usage: obj.testDavidsonHarel() without return types