code: def test_gmm_fit(backend):
      """Test GMM detector fit method.
  
      Tests detector checks for convergence and stops early if it does.
      """
      gmm = GMM(n_components=1, backend=backend)
      mean = [8, 8]
      cov = [[2.0, 0.0], [0.0, 1.0]]
      x_ref = torch.tensor(
          np.random.multivariate_normal(mean, cov, 1000)
      )
      fit_results = gmm.fit(x_ref, tol=0.01, batch_size=32)
      assert isinstance(fit_results["lower_bound"], float)
      assert fit_results["converged"]
      assert fit_results["lower_bound"] < 1
  
file_path: alibi-detect/alibi_detect/od/tests/test__gmm/test__gmm.py
imports: import pytest
  import numpy
  import torch
  from alibi_detect.od._gmm import GMM
  from alibi_detect.exceptions import NotFittedError
  from sklearn.datasets import make_moons
label_desc: Use image node_id 6 for calling a global function with example usage: test_gmm_fit(backend) without return types