code: def _test_function_x_y_dy(x, y, dy, eps=0.01):
      """Builds a polynomial with (approx) given values and derivatives."""
      x1 = x + eps
      y1 = y + eps * dy
      x2 = x - eps
      y2 = y - eps * dy
      return _test_function_x_y(
          np.concatenate([x1, x2], axis=-1),
          np.concatenate([y1, y2], axis=-1),
      )
  
imports: import collections
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math.gradient import value_and_gradient
  from tensorflow_probability.python.optimizer.linesearch.internal import hager_zhang_lib
label_desc: Use image node_id 3 for calling a global function with example usage: _test_function_x_y_dy(x, y, dy, eps) and returns: _test_function_x_y