code: def test_valid_polygon(self):
      poly = geojson.Polygon(
          [
              [
                  (2.38, 57.322),
                  (23.194, -20.28),
                  (-120.43, 19.15),
                  (2.38, 57.322),
              ]
          ]
      )
      self.assertEqual(poly.is_valid, True)
  
imports: import unittest
  import geojson
label_desc: Use image node_id 2 for calling the TestValidationPolygon obj's underlying member method code with example usage: obj.test_valid_polygon() without return types