code: def get_data_home(data_home=None):
      """Return the path of the arviz data dir.
  
      This folder is used by some dataset loaders to avoid downloading the
      data several times.
  
      By default the data dir is set to a folder named 'arviz_data' in the
      user home folder.
  
      Alternatively, it can be set by the 'ARVIZ_DATA' environment
      variable or programmatically by giving an explicit folder path. The '~'
      symbol is expanded to the user home folder.
  
      If the folder does not already exist, it is automatically created.
  
      Parameters
      ----------
      data_home : str | None
          The path to arviz data dir.
      """
      if data_home is None:
          data_home = os.environ.get(
              "ARVIZ_DATA", os.path.join("~", "arviz_data")
          )
      data_home = os.path.expanduser(data_home)
      if not os.path.exists(data_home):
          os.makedirs(data_home)
      return data_home
  
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 1 for calling a global function with example usage: get_data_home(data_home) and returns: data_home