code: def data_available(dataset_name=None):
      
      try:
          from itertools import zip_longest
      except ImportError:
          from itertools import izip_longest as zip_longest
      dr = data_resources[dataset_name]
      zip_urls = (dr['files'], )
      if 'save_names' in dr: zip_urls += (dr['save_names'], )
      else: zip_urls += ([],)
  
      for file_list, save_list in zip_longest(*zip_urls, fillvalue=[]):
          for f, s in zip_longest(file_list, save_list, fillvalue=None):
              if s is not None: f=s # If there is a save_name given, use that one
              if not os.path.exists(os.path.join(data_path, dataset_name, f)):
                  return False
      return True
docs: Check if the data set is available on the local machine already.