docstr: Test that generated structure has expected number of nodes = num_nodes
docstr_tok: ["Test","that","generated","structure","has","expected","number","of","nodes","=","num_nodes"]
code: def test_expected_num_nodes(self, num_nodes, degree):
      """Test that generated structure has expected number of nodes = num_nodes"""
      sm = generate_structure(num_nodes, degree)
      assert len(sm.nodes) == num_nodes
  
imports: import operator
  from typing import Hashable, Tuple, Union
  import networkx
  import numpy
  import pandas
  import pytest
  from networkx.algorithms.dag import is_directed_acyclic_graph
  from sklearn.gaussian_process.kernels import RBF
  from causalnex.structure.data_generators.core import _sample_binary_from_latent, _sample_count_from_latent, _sample_poisson, generate_structure, nonlinear_sem_generator, sem_generator
  from causalnex.structure.structuremodel import StructureModel
label_desc: Use image node_id 4 for calling the TestGenerateStructure obj's underlying member method code with example usage: obj.test_expected_num_nodes(num_nodes, degree) without return types