code: def _get_data_path(data_dir=None):
      
      data_dir = data_dir or ''
  
      default_dirs = [Path(d).expanduser().resolve()
                      for d in os.getenv('CRN_SHARED_DATA', '').split(os.pathsep)
                      if d.strip()]
      default_dirs += [Path(d).expanduser().resolve()
                       for d in os.getenv('CRN_DATA', '').split(os.pathsep)
                       if d.strip()]
      default_dirs += [NIWORKFLOWS_CACHE_DIR]
  
      return [Path(d).expanduser()
              for d in data_dir.split(os.pathsep) if d.strip()] or default_dirs
docs: Get data storage directory
  
      data_dir: str
        Path of the data directory. Used to force data storage in
        a specified location.
  
      :returns:
          a list of paths where the dataset could be stored,
          ordered by priority