code: def get_message_headers(self, section: Sequence[int] = None,
                              subset: Collection[bytes] = None,
                              inverse: bool = False) -> Writeable:
          
          ...
docs: Get the headers from the message or a ``message/rfc822`` sub-part of
          the message..
  
          The ``section`` argument can index a nested sub-part of the message.
          For example, ``[2, 3]`` would get the 2nd sub-part of the message and
          then index it for its 3rd sub-part.
  
          Args:
              section: Optional nested list of sub-part indexes.
              subset: Subset of headers to get.
              inverse: If ``subset`` is given, this flag will invert it so that
                  the headers *not* in ``subset`` are returned.