code: def parse_dataset_key(dataset_key):
      
      match = re.match(DATASET_KEY_PATTERN, dataset_key)
      if not match:
          raise ValueError('Invalid dataset key. Key must include user and '
                           'dataset names, separated by (i.e. user/dataset).')
      return match.groups()
docs: Parse a dataset URL or path and return the owner and the dataset id
  
      :param dataset_key: Dataset key (in the form of owner/id) or dataset URL
      :type dataset_key: str
      :returns: User name of the dataset owner and ID of the dataset
      :rtype: dataset_owner, dataset_id
      :raises ValueError: If the provided key does comply to the expected pattern
  
      Examples
      --------
      >>> from datadotworld import util
      >>> util.parse_dataset_key(
      ...     'https://data.world/jonloyens/an-intro-to-datadotworld-dataset')
      ('jonloyens', 'an-intro-to-datadotworld-dataset')
      >>> util.parse_dataset_key('jonloyens/an-intro-to-datadotworld-dataset')
      ('jonloyens', 'an-intro-to-datadotworld-dataset')