      # METHODS THAT DO DATABASE QUERIES #
      ####################################
  
      def iterator(self, chunk_size=2000):
          """
          An iterator over the results from applying this QuerySet to the
          database.
 
</s> remove         for row in compiler.results_iter():
            yield row[0]
 </s> add         return chain.from_iterable(compiler.results_iter()) </s> remove         return iter(self._iterable_class(self, chunked_fetch=use_chunked_fetch, chunk_size=chunk_size))
 </s> add         return self._iterator(use_chunked_fetch, chunk_size)
    def _iterator(self, use_chunked_fetch, chunk_size):
        yield from self._iterable_class(self, chunked_fetch=use_chunked_fetch, chunk_size=chunk_size)

      # METHODS THAT DO DATABASE QUERIES #
      ####################################
  
    def _iterator(self, use_chunked_fetch, chunk_size):
        yield from self._iterable_class(self, chunked_fetch=use_chunked_fetch, chunk_size=chunk_size)

      def iterator(self, chunk_size=2000):
          """
          An iterator over the results from applying this QuerySet to the
          database.
keep keep add keep keep keep keep
 Refs #28459 -- Improved performance of FlatValuesListIterable. 
django/db/models/query.py