class_docstr: Encapsulate CmdStanPy specific logic.
docstr: Extract sample_stats from prior fit.
code: def sample_stats_prior_to_xarray(self):
      """Extract sample_stats from prior fit."""
      return self.stats_to_xarray(self.prior)
  
imports: import logging
  import re
  from collections import defaultdict
  from copy import deepcopy
  from pathlib import Path
  import numpy
  from ..rcparams import rcParams
  from .base import dict_to_dataset, infer_stan_dtypes, make_attrs, requires
  from .inference_data import InferenceData
label_desc: Use image node_id 4 for calling the CmdStanPyConverter obj's underlying member method code with example usage: obj.sample_stats_prior_to_xarray() and returns: self