code: def test_median(self):
      assert_almost_equal(np.median(self.chem), 3.385, DECIMAL)
  
imports: import numpy
  from numpy.random import standard_normal
  from numpy.testing import assert_almost_equal, assert_equal
  import pytest
  from scipy.stats import norm
  import statsmodels.api
  import statsmodels.robust.scale
  from statsmodels.robust.scale import mad
label_desc: Use image node_id 3 for calling the TestChem obj's underlying member method code with example usage: obj.test_median() without return types