code: def _tolerance(X, tol):
      """Return a tolerance which is dependent on the dataset."""
      if tol == 0:
          return 0
      if sp.issparse(X):
          variances = mean_variance_axis(X, axis=0)[1]
      else:
          variances = np.var(X, axis=0)
      return np.mean(variances) * tol
  
imports: import warnings
  from abc import ABC, abstractmethod
  from numbers import Integral, Real
  import numpy
  import scipy.sparse
  from ..base import BaseEstimator, ClassNamePrefixFeaturesOutMixin, ClusterMixin, TransformerMixin, _fit_context
  from ..exceptions import ConvergenceWarning
  from ..metrics.pairwise import _euclidean_distances, euclidean_distances
  from ..utils import check_array, check_random_state
  from ..utils._openmp_helpers import _openmp_effective_n_threads
  from ..utils._param_validation import Hidden, Interval, StrOptions, validate_params
  from ..utils.extmath import row_norms, stable_cumsum
  from ..utils.fixes import threadpool_info, threadpool_limits
  from ..utils.sparsefuncs import mean_variance_axis
  from ..utils.sparsefuncs_fast import assign_rows_csr
  from ..utils.validation import _check_sample_weight, _is_arraylike_not_scalar, check_is_fitted
  from ._k_means_common import CHUNK_SIZE, _inertia_dense, _inertia_sparse, _is_same_clustering
  from ._k_means_elkan import elkan_iter_chunked_dense, elkan_iter_chunked_sparse, init_bounds_dense, init_bounds_sparse
  from ._k_means_lloyd import lloyd_iter_chunked_dense, lloyd_iter_chunked_sparse
  from ._k_means_minibatch import _minibatch_update_dense, _minibatch_update_sparse
label_desc: Use image node_id 3 for calling a global function with example usage: _tolerance(X, tol) and returns: unknown, int