code: def test_init(barbell):
      generator = GraphWaveGenerator(
          barbell, scales=(0.1, 2, 3, 4), degree=10
      )
  
      np.testing.assert_array_equal(
          generator.scales, np.array((0.1, 2, 3, 4)).astype(np.float32)
      )
      assert generator.coeffs.shape == (4, 10 + 1)
      assert generator.laplacian.shape == (
          barbell.number_of_nodes(),
          barbell.number_of_nodes(),
      )
  
file_path: stellargraph/tests/mapper/test_graphwave_generator.py
imports: from stellargraph.core.graph import *
  from stellargraph.mapper.graphwave_generator import GraphWaveGenerator, _empirical_characteristic_function
  from ..test_utils.graphs import barbell
  import numpy
  import pytest
  import scipy.sparse
  import tensorflow
label_desc: Use image node_id 2 for calling a global function with example usage: test_init(barbell) without return types