old_contents: #unit test
  """ doc string"""
  import unittest
  from addition import add
  A='7'
  B='5'
  C='0'
  D='0'
  class AdditionTestCase(unittest.TestCase):
      """Tests for `addtion.py`"""
  
      def test_is_valid_input(self):
          """checking for input in codes"""
          self.assertTrue(add(A, B))
      def test_is_valid_input(self):
          """checking for input in codes"""
          self.assertTrue(add(A, C))  
      def test_is_alphabetl(self):
          """testing for alphabets"""
          self.assertFalse(A.islower())
      def test_is_valid_input2(self):
          """testing for normal integers"""
          self.assertFalse(add(C, D))
      def test_is_alphabetu(self):
          """testing for digits"""
          self.assertTrue(A.isdigit())
  if __name__ == '__main__':
      unittest.main()
  
new_contents: #unit test
  """ doc string"""
  import unittest
  from addition import add
  A='7'
  B='5'
  C='0'
  D='0'
  class AdditionTestCase(unittest.TestCase):
      """Tests for `addtion.py`"""
  
      def test_is_valid_input(self):
          """checking for input in codes"""
          self.assertTrue(add(A, B))
      def test_is_valid_input2(self):
          """checking for input in codes"""
          self.assertTrue(add(A, C))  
      def test_is_alphabetl(self):
          """testing for alphabets"""
          self.assertFalse(A.islower())
      def test_is_valid_input3(self):
          """testing for normal integers"""
          self.assertFalse(add(C, D))
      def test_is_alphabetu(self):
          """testing for digits"""
          self.assertTrue(A.isdigit())
  if __name__ == '__main__':
      unittest.main()
  
subject: Create test_addition.py