code: def _rational_quadratic(
      self, amplitude, length_scale, scale_mixture_rate, x, y
  ):
      return (amplitude**2) * (
          1.0
          + np.sum((x - y) ** 2)
          / (2 * scale_mixture_rate * length_scale**2)
      ) ** (-scale_mixture_rate)
  
file_path: probability/tensorflow_probability/python/math/psd_kernels/rational_quadratic_test.py
imports: from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math.psd_kernels import rational_quadratic
label_desc: Use image node_id 1 for calling the RationalQuadraticTest obj's underlying member method code with example usage: obj._rational_quadratic(amplitude, length_scale, scale_mixture_rate, x, y) and returns: unknown