old_contents: """Tests for pyswarm."""
  from unittest import TestCase
  from grortir.externals.pyswarm.pso import pso
  
  
  class TestPso(TestCase):
      """Class for tests PSO."""
  
      def test_run_simple_pso(self):
          """Test running library."""
          lower_bound = [-3, -1]
          upper_bound = [2, 6]
  
          x_opt, f_opt = pso(myfunc, lower_bound, upper_bound)
          self.assertIsNotNone(x_opt)
          self.assertIsNotNone(f_opt)
  
  
  def myfunc(input_vector):
      """Simple function for tests.
  
      Args:
          input_vector: input vector
  
      Returns:
          object : value of function
      """
      x_1 = input_vector[0]
      x_2 = input_vector[1]
      return x_1 ** 4 - 2 * x_2 * x_1 ** 2 + x_2 ** 2 + x_1 ** 2 - 2 * x_1 + 5
  
new_contents: """Tests for pyswarm."""
  from unittest import TestCase
  from grortir.externals.pyswarm.pso import pso
  
  
  class TestPso(TestCase):
      """Class for tests pyswarm."""
  
      def test_run_simple_pso(self):
          """Test running library."""
          lower_bound = [-3, -1]
          upper_bound = [2, 6]
  
          x_opt, f_opt = pso(myfunc, lower_bound, upper_bound)
          self.assertIsNotNone(x_opt)
          self.assertIsNotNone(f_opt)
  
  
  def myfunc(input_vector):
      """Simple function for tests.
  
      Args:
          input_vector (list): input vector
  
      Returns:
          object : value of function
      """
      x_1 = input_vector[0]
      x_2 = input_vector[1]
      return x_1 ** 4 - 2 * x_2 * x_1 ** 2 + x_2 ** 2 + x_1 ** 2 - 2 * x_1 + 5
  
subject: Add pySwarm code - tests fixed.