code: def lookup(self, iterable, gather=False):
          
          for result in self.root.lookup(iterable,
                                         gather=gather,
                                         edit_distance=0,
                                         max_edit_distance=self.max_edit_distance,
                                         match_threshold=self.match_threshold):
              yield result
docs: Call the lookup on the root node with the given parameters.
  
          Args
              iterable(index or key): Used to retrive nodes from tree
              gather(bool): this is passed down to the root node lookup
  
          Notes:
              max_edit_distance and match_threshold come from the init