old_contents: """
  Tests for dit.math.sigmaalgebra.
  """
  import pytest
  
  from dit.math.sigmaalgebra import is_sigma_algebra, is_sigma_algebra__brute, atom_set
  
  
  sa = frozenset([frozenset([]), frozenset(['a']), frozenset(['b']), frozenset(['c']), 
                  frozenset(['a', 'b']), frozenset(['a', 'c']), frozenset(['b', 'c']),
                  frozenset(['a', 'b', 'c'])])
  not_sa1 = frozenset([frozenset([]), frozenset('c'), frozenset(['a', 'b'])])
  not_sa2 = frozenset([frozenset([]), frozenset(['a']), frozenset(['b']), frozenset(['c']), 
                  frozenset(['a', 'b']), frozenset(['a', 'c']), frozenset(['b', 'c'])])
  
  
  def test_isa1():
      """
      Test SA.
      """
      assert is_sigma_algebra(sa)
  
  
  def test_isa2():
      """
      Test not SA.
      """
      
      assert not is_sigma_algebra(not_sa1)
  
  
  def test_isa3():
      """
      Test not SA.
      """
      
      assert not is_sigma_algebra(not_sa2)
  
  
  def test_isa4():
      """
      Test SA brute.
      """
      assert is_sigma_algebra__brute(sa)
  
  
  def test_isa5():
      """
      Test not SA brute.
      """
      assert not is_sigma_algebra__brute(not_sa1)
  
  
  def test_isa6():
      """
      Test not SA brute.
      """
      assert not is_sigma_algebra__brute(not_sa2, X=['a', 'b', 'c'])
  
  
  def test_atom_set1():
      """
      Find the atoms.
      """
      atoms = atom_set(sa)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  
  def test_atom_set2():
      """
      Find the atoms.
      """
      atoms = atom_set(not_sa1, method=1)
      assert atoms == frozenset([frozenset('c')])
  
  
  def test_atom_set3():
      """
      Find the atoms.
      """
      atoms = atom_set(not_sa2, method=1)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  
  def test_atom_set4():
      """
      Find the atoms.
      """
      atoms = atom_set(sa, method=1)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  def test_atom_set5():
      """
      Test failure.
      """
      with pytest.raises(Exception):
          atom_set('pants')
  
new_contents: """
  Tests for dit.math.sigmaalgebra.
  """
  import pytest
  
  from dit.math.sigmaalgebra import is_sigma_algebra, is_sigma_algebra__brute, atom_set
  
  
  sa = frozenset([frozenset([]), frozenset(['a']), frozenset(['b']), frozenset(['c']), 
                  frozenset(['a', 'b']), frozenset(['a', 'c']), frozenset(['b', 'c']),
                  frozenset(['a', 'b', 'c'])])
  not_sa1 = frozenset([frozenset([]), frozenset('c'), frozenset(['a', 'b'])])
  not_sa2 = frozenset([frozenset([]), frozenset(['a']), frozenset(['b']), frozenset(['c']), 
                  frozenset(['a', 'b']), frozenset(['a', 'c']), frozenset(['b', 'c'])])
  
  
  def test_isa1():
      """
      Test SA.
      """
      assert is_sigma_algebra(sa)
  
  
  def test_isa2():
      """
      Test not SA.
      """
      
      assert not is_sigma_algebra(not_sa1)
  
  
  def test_isa3():
      """
      Test not SA.
      """
      
      assert not is_sigma_algebra(not_sa2)
  
  
  def test_isa4():
      """
      Test SA brute.
      """
      assert is_sigma_algebra__brute(sa)
  
  
  def test_isa5():
      """
      Test not SA brute.
      """
      assert not is_sigma_algebra__brute(not_sa1)
  
  
  def test_isa6():
      """
      Test not SA brute.
      """
      assert not is_sigma_algebra__brute(not_sa2, X=['a', 'b', 'c'])
  
  
  def test_atom_set1():
      """
      Find the atoms.
      """
      atoms = atom_set(sa)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  
  def test_atom_set2():
      """
      Find the atoms.
      """
      atoms = atom_set(not_sa1, method=1)
      assert atoms == frozenset([frozenset('c'), frozenset(['a', 'b'])])
  
  
  def test_atom_set3():
      """
      Find the atoms.
      """
      atoms = atom_set(not_sa2, method=1)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  
  def test_atom_set4():
      """
      Find the atoms.
      """
      atoms = atom_set(sa, method=1)
      assert atoms == frozenset([frozenset('a'), frozenset('b'), frozenset('c')])
  
  def test_atom_set5():
      """
      Test failure.
      """
      with pytest.raises(Exception):
          atom_set('pants')
  
subject: fix a test