code: def test_autocorrelation():
      x = torch.arange(10.0)
      actual = autocorrelation(x)
      assert_equal(
          actual,
          torch.tensor(
              [
                  1,
                  0.78,
                  0.52,
                  0.21,
                  -0.13,
                  -0.52,
                  -0.94,
                  -1.4,
                  -1.91,
                  -2.45,
              ]
          ),
          prec=0.01,
      )
  
imports: import warnings
  import pytest
  import torch
  from pyro.ops.stats import _cummin, autocorrelation, autocovariance, crps_empirical, effective_sample_size, fit_generalized_pareto, gelman_rubin, hpdi, pi, quantile, resample, split_gelman_rubin, waic
  from tests.common import assert_close, assert_equal, xfail_if_not_implemented
label_desc: Use image node_id 9 for calling a global function with example usage: test_autocorrelation() without return types