new_contents: import pytest
  
  from choo.types import Coordinates
  
  
  class TestCoordinates:
      def test_distance(self):
          assert round(Coordinates(51.451379, 7.013569).distance_to(Coordinates(51.454726, 6.979494)), 3) == 2390.268
          with pytest.raises(TypeError):
              Coordinates(51.451379, 7.013569).distance_to(7)
  
      def test_serialize(self):
          assert tuple(Coordinates(51.451379, 7.013569).serialize()) == (51.451379, 7.013569)
  
      def test_unserialize(self):
          assert Coordinates(51.451379, 7.013569) == Coordinates.unserialize((51.451379, 7.013569))
  
      def test_reversed(self):
          assert reversed(Coordinates(51.451379, 7.013569)) == (7.013569, 51.451379)
  
subject: add TestCoordinates