code: def test_construct_drift_default(self):
      dtypes = [tf.float64, tf.float32]
      for dtype in dtypes:
          drift_fn, total_drift_fn = bm_utils.construct_drift_data(
              None, None, 2, dtype
          )
          times = tf.constant([0.3, 0.9, 1.5], dtype=dtype)
          drift_vals = self.evaluate(drift_fn(times))
          np.testing.assert_array_equal(drift_vals.shape, [3, 2])
          np.testing.assert_allclose(
              drift_vals, [[0.0, 0], [0, 0], [0, 0]]
          )
          total_vals = self.evaluate(total_drift_fn(times - 0.2, times))
          np.testing.assert_array_equal(total_vals.shape, [3, 2])
          np.testing.assert_allclose(
              total_vals, [[0.0, 0], [0, 0], [0, 0]]
          )
  
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow.python.framework import test_util
  from tf_quant_finance.models.legacy import brownian_motion_utils
label_desc: Use image node_id 3 for calling the BrownianMotionUtilsTest obj's underlying member method code with example usage: obj.test_construct_drift_default() without return types