code: def _sha256(path):
      """Calculate the sha256 hash of the file at path."""
      sha256hash = hashlib.sha256()
      chunk_size = 8192
      with open(path, "rb") as buff:
          while True:
              buffer = buff.read(chunk_size)
              if not buffer:
                  break
              sha256hash.update(buffer)
      return sha256hash.hexdigest()
  
file_path: arviz/arviz/data/datasets.py
imports: import hashlib
  import itertools
  import json
  import os
  import shutil
  from collections import namedtuple
  from urllib.request import urlretrieve
  from ..rcparams import rcParams
  from .io_netcdf import from_netcdf
label_desc: Use image node_id 3 for calling a global function with example usage: _sha256(path) and returns: sha256hash