docstr: Test using externally specified interpolator.
docstr_tok: ["Test","using","externally","specified","interpolator","."]
code: def test_volatility_2d_interpolation(self):
      """Test using externally specified interpolator."""
      vol_surface = build_surface(2, False)
      expiry = tff.datetime.dates_from_ordinals(
          [[737592, 737942, 739252], [737592, 737942, 739252]]
      )
      vols = vol_surface.volatility(
          strike=[[1525, 1400, 1570], [1525, 1505, 1570]],
          expiry_dates=expiry,
      )
      self.assertAllClose(
          self.evaluate(vols),
          [
              [0.14046875, 0.11547945, 0.1],
              [0.14046875, 0.12300392, 0.1],
          ],
          atol=1e-6,
      )
  
file_path: tf-quant-finance/tf_quant_finance/experimental/pricing_platform/framework/market_data/volatility_surface_test.py
imports: from absl.testing import parameterized
  import tensorflow.compat.v2
  import tf_quant_finance
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 3 for calling the VolatilitySurfaceTest obj's underlying member method code with example usage: obj.test_volatility_2d_interpolation() without return types