code: def _dtype(self):
      return jnp.float64
  
imports: import functools
  import os
  import jax
  from jax import config
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import test_util
  from fun_mc import backend
  from fun_mc import fun_mc_lib
  from fun_mc import prefab
  from fun_mc import test_util
  from fun_mc import util_tfp
label_desc: Use image node_id 1 for calling the PrefabTest64 obj's underlying member method code with example usage: obj._dtype() and returns: jnp