old_contents: from unittest import TestCase
  
  from address_book import AddressBook, Person, Group
  
  
  class AddressBookTestCase(TestCase):
  
      def test_add_person(self):
          address_book = AddressBook()
          person = Person(
              'John',
              'Doe',
              ['Russian Federation, Kemerovo region, Kemerovo, Kirova street 23, apt. 42'],
              ['+79834772053']
          )
          address_book.add_person(person)
          self.assertIn(person, address_book)
  
      def test_add_group(self):
          address_book = AddressBook()
          group = Group('Brozzz')
          address_book.add_group(group)
          self.assertIn(group, address_book)
  
      def test_find_person_by_first_name(self):
          pass
  
      def test_find_person_by_last_name(self):
          pass
  
      def test_find_person_by_email(self):
          pass
new_contents: from unittest import TestCase
  
  from address_book import AddressBook, Person, Group
  
  
  class AddressBookTestCase(TestCase):
  
      def test_add_person(self):
          address_book = AddressBook()
          person = Person(
              'John',
              'Doe',
              ['Russian Federation, Kemerovo region, Kemerovo, Kirova street 23, apt. 42'],
              ['+79834772053']
          )
          address_book.add_person(person)
          self.assertIn(person, address_book)
  
      def test_add_group(self):
          address_book = AddressBook()
          group = Group('Brozzz')
          address_book.add_group(group)
          self.assertIn(group, address_book)
  
      def test_find_person_by_first_name(self):
          address_book = AddressBook()
          john_person = Person(
              'John',
              'Doe',
              ['Russian Federation, Kemerovo region, Kemerovo, Kirova street 23, apt. 42'],
              ['+79834772053']
          )
          ivan_person = Person(
              'Ivan',
              'Doe',
              ['Russian Federation, Kemerovo region, Belovo, Kirova street 42, apt. 13'],
              ['+79834771122']
          )
          found_person = address_book.find(first_name='Ivan')
          self.assertEqual(found_person, ivan_person)
  
      def test_find_person_by_last_name(self):
          pass
  
      def test_find_person_by_email(self):
          pass
subject: Add test for finding a person by first name