code: def test_retraction(self, tangent_vec, base_point, expected, atol):
      res = self.space.metric.retraction(tangent_vec, base_point)
      self.assertAllClose(res, expected, atol=atol)
  
file_path: geomstats/geomstats/test_cases/geometry/poincare_ball.py
imports: import pytest
  import geomstats.backend
  from geomstats.test.vectorization import generate_vectorization_data
  from geomstats.test_cases.geometry.base import VectorSpaceOpenSetTestCase
  from geomstats.test_cases.geometry.riemannian_metric import RiemannianMetricTestCase
label_desc: Use image node_id 3 for calling the PoincareBallMetricTestCase obj's underlying member method code with example usage: obj.test_retraction(tangent_vec, base_point, expected, atol) without return types