code: def variance_estimators(request):
      request.cls.space = request.param
  
imports: import random
  import pytest
  from geomstats.geometry.discrete_curves import DiscreteCurvesStartingAtOrigin, ElasticTranslationMetric
  from geomstats.geometry.euclidean import Euclidean
  from geomstats.geometry.hyperboloid import Hyperboloid
  from geomstats.geometry.hypersphere import Hypersphere
  from geomstats.geometry.matrices import Matrices
  from geomstats.geometry.minkowski import Minkowski
  from geomstats.geometry.spd_matrices import SPDMatrices
  from geomstats.geometry.special_orthogonal import SpecialOrthogonal
  from geomstats.learning.frechet_mean import BatchGradientDescent, FrechetMean, GradientDescent
  from geomstats.test.parametrizers import DataBasedParametrizer
  from geomstats.test_cases.learning._base import BaseEstimatorTestCase
  from geomstats.test_cases.learning.frechet_mean import BatchGradientDescentTestCase, CircularMeanTestCase, ElasticMeanTestCase, FrechetMeanTestCase, VarianceTestCase
  from .data.frechet_mean import BatchGradientDescentTestData, CircularMeanTestData, FrechetMeanSOCoincideTestData, FrechetMeanTestData, LinearMeanEuclideaTestData, VarianceEuclideanTestData, VarianceTestData
label_desc: Use image node_id 4 for calling a global function with example usage: variance_estimators(request) without return types