text: from is_valid_walk import is_valid_walk
  import unittest
  
  
  class Test(unittest.TestCase):
      def test_1(self):
          result = is_valid_walk(["n", "s", "n", "s", "n",
                                  "s", "n", "s", "n", "s"])
          self.assertEqual(result, True)
  
      def test_2(self):
          result = is_valid_walk(
              ["w", "e", "w", "e", "w", "e", "w", "e", "w", "e", "w", "e"]
          )
          self.assertEqual(result, False)
  
  
  if __name__ == "__main__":
      unittest.main()
  