docs: def directives(entrystream, type=None):
      """
      Pull directives out of the specified entry stream.
  
      :param entrystream: a stream of entries
      :param type: retrieve only directives of the specified type; set to
                   :code:`None` to retrieve all directives
      """
      for directive in entry_type_filter(entrystream, tag.Directive):
          if not type or type == directive.type:
              yield directive