code: def get_key(self, match_key, num_results=1, best=True, **dfilter):
          
          return get_key(match_key, self.keys(), num_results=num_results,
                         best=best, **dfilter)
docs: Get multiple fully-specified keys that match the provided query.
  
          Args:
              key (DatasetID): DatasetID of query parameters to use for
                               searching. Any parameter that is `None`
                               is considered a wild card and any match is
                               accepted. Can also be a string representing the
                               dataset name or a number representing the dataset
                               wavelength.
              num_results (int): Number of results to return. If `0` return all,
                                 if `1` return only that element, otherwise
                                 return a list of matching keys.
              **dfilter (dict): See `get_key` function for more information.