code: def _np_kernel_matrix_fn(amp, len_scale, x, y):
      x = np.expand_dims(x, -2)[..., 0]
      y = np.expand_dims(y, -3)[..., 0]
      return amp**2 * np.exp(-0.5 * ((x - y) ** 2) / (len_scale**2))
  
imports: from unittest import mock
  from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import gaussian_process
  from tensorflow_probability.python.distributions import gaussian_process_regression_model
  from tensorflow_probability.python.internal import tensorshape_util
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math.psd_kernels import exp_sin_squared
  from tensorflow_probability.python.math.psd_kernels import exponentiated_quadratic
  from tensorflow_probability.python.math.psd_kernels.internal import test_util
label_desc: Use image node_id 1 for calling a global function with example usage: _np_kernel_matrix_fn(amp, len_scale, x, y) and returns: unknown