code: def _get_nabla_x_y(
      self, horizontal_vec_x, vec_y, base_point, horizontal=True
  ):
      a_x_y = self.bundle.integrability_tensor(
          horizontal_vec_x, vec_y, base_point
      )
  
      dy = (
          self._get_horizontal_vec(base_point)
          if horizontal
          else self._get_vertical_vec(base_point)
      )
  
      return a_x_y + dy
  
imports: import pytest
  import geomstats.backend
  from geomstats.geometry.matrices import Matrices
  from geomstats.test.random import KendalShapeRandomDataGenerator, get_random_times
  from geomstats.test.vectorization import generate_vectorization_data
  from geomstats.test_cases.geometry.base import LevelSetTestCase
  from geomstats.test_cases.geometry.fiber_bundle import FiberBundleTestCase
  from geomstats.test_cases.geometry.quotient_metric import QuotientMetricTestCase
  from geomstats.vectorization import get_batch_shape
label_desc: Use image node_id 4 for calling the PreShapeSpaceBundleTestCase obj's underlying member method code with example usage: obj._get_nabla_x_y(horizontal_vec_x, vec_y, base_point, horizontal) and returns: unknown