code: def each_indexed_object(collection, index_name, **where):
      
      index = _db[collection].indexes[index_name]
      for id in index.value_map.get(indexed_value(index, where), []):
          yield get_object(collection, id)
docs: Yields each object indexed by the index with
      name ``name`` with ``values`` matching on indexed
      field values.