old_contents: from lexos.helpers.error_messages import SEG_NON_POSITIVE_MESSAGE
  from lexos.models.topword_model import TopwordModel
  
  
  #
  class TestZTest:
      def test_normal_case(self):
          assert round(TopwordModel._z_test(p1=0.1, pt=0.3, n1=100, nt=10000), 2) == -4.35
          assert round(TopwordModel._z_test(p1=0.3, pt=0.1, n1=100, nt=100), 2) == 3.54
          assert TopwordModel._z_test(p1=1, pt=1, n1=100, nt=100) == 0
  
      def test_special_case(self):
          try:
              _ = TopwordModel._z_test(p1=0.1, pt=0.3, n1=100, nt=0)
              raise AssertionError("Error message did not raise")
          except AssertionError as error:
              assert str(error) == SEG_NON_POSITIVE_MESSAGE
  
          try:
              _ = TopwordModel._z_test(p1=0.1, pt=0.3, n1=0, nt=100)
              raise AssertionError("Error message did not raise")
          except AssertionError as error:
              assert str(error) == SEG_NON_POSITIVE_MESSAGE
  
new_contents: from lexos.helpers.error_messages import SEG_NON_POSITIVE_MESSAGE
  from lexos.models.topword_model import TopwordModel
  
  
  class TestZTest:
      def test_normal_case(self):
          assert round(TopwordModel._z_test(p1=0.1, pt=0.3, n1=10, nt=1000), 2) \
              == -1.38
          assert round(TopwordModel._z_test(p1=0.3, pt=0.1, n1=100, nt=100), 2) \
              == 3.54
          assert TopwordModel._z_test(p1=1, pt=1, n1=100, nt=100) == 0
  
      def test_special_case(self):
          try:
              _ = TopwordModel._z_test(p1=0.1, pt=0.3, n1=100, nt=0)
              raise AssertionError("Error message did not raise")
          except AssertionError as error:
              assert str(error) == SEG_NON_POSITIVE_MESSAGE
  
          try:
              _ = TopwordModel._z_test(p1=0.1, pt=0.3, n1=0, nt=100)
              raise AssertionError("Error message did not raise")
          except AssertionError as error:
              assert str(error) == SEG_NON_POSITIVE_MESSAGE
  
subject: Fix indentation errors