code: def test_cov_trob_2d():
      x = np.array(data[["x", "y"]])
      res = cov_trob(x, cor=True)
  
      # Values from MASS::cov.trob
      n_obs = 5
      center = [3.110130, 4.359847]
      cov = [[1.979174, 2.812684], [2.812684, 4.584488]]
      cor = [[1.0000000, 0.9337562], [0.9337562, 1.0000000]]
  
      assert res["n_obs"] == n_obs
      npt.assert_allclose(res["center"], center)
      npt.assert_allclose(res["cov"], cov)
      npt.assert_allclose(res["cor"], cor)
  
imports: import numpy
  import numpy.testing
  import pandas
  from plotnine import aes, geom_point, ggplot, stat_ellipse
  from plotnine.stats.stat_ellipse import cov_trob
label_desc: Use image node_id 2 for calling a global function with example usage: test_cov_trob_2d() without return types