code: def test_balanced_tree(self):
      # balanced_tree(r,h) is a tree with (r**(h+1)-1)/(r-1) edges
      for r, h in [(2, 2), (3, 3), (6, 2)]:
          t = nx.balanced_tree(r, h)
          order = t.order()
          assert order == (r ** (h + 1) - 1) / (r - 1)
          assert nx.is_connected(t)
          assert t.size() == order - 1
          dh = nx.degree_histogram(t)
          assert dh[0] == 0  # no nodes of 0
          assert dh[1] == r**h  # nodes of degree 1 are leaves
          assert dh[r] == 1  # root is degree r
          assert (
              dh[r + 1] == order - r**h - 1
          )  # everyone else is degree r+1
          assert len(dh) == r + 2
  
imports: import itertools
  import typing
  import pytest
  import networkx
  from networkx.algorithms.isomorphism.isomorph import graph_could_be_isomorphic
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 1 for calling the TestGeneratorClassic obj's underlying member method code with example usage: obj.test_balanced_tree() without return types