code: def setup_class(cls):
      cls.rng = RandomState(12345)
      cls.T = 1000
      cls.resids = cls.rng.standard_normal(cls.T)
      cls.sigma2 = 1 + cls.rng.random_sample(cls.resids.shape)
  
file_path: arch/arch/tests/univariate/test_distribution.py
imports: import numpy
  from numpy.random import RandomState, default_rng
  from numpy.testing import assert_almost_equal, assert_array_equal, assert_equal
  import pytest
  from scipy.special import gamma, gammaln
  import scipy.stats
  from arch.univariate.distribution import GeneralizedError, Normal, SkewStudent, StudentsT
label_desc: Use image node_id 1 for calling the TestDistributions obj's underlying member method code with example usage: obj.setup_class(cls) without return types