code: def test_gmm_sklearn_fit():
      """Test GMM detector sklearn backend fit method.
  
      Tests the scoring method of the GMMSklearn backend detector.
      """
      gmm_sklearn = GMMSklearn(n_components=1)
      mean = [8, 8]
      cov = [[2.0, 0.0], [0.0, 1.0]]
      x_ref = np.random.multivariate_normal(mean, cov, 1000)
      fit_results = gmm_sklearn.fit(x_ref, tol=0.01)
      assert fit_results["converged"]
      assert fit_results["n_iter"] < 10
      assert fit_results["lower_bound"] < 1
  
imports: import pytest
  import numpy
  from alibi_detect.od.sklearn.gmm import GMMSklearn
  from alibi_detect.exceptions import NotFittedError, ThresholdNotInferredError
label_desc: Use image node_id 3 for calling a global function with example usage: test_gmm_sklearn_fit() without return types