'Provide the metafile metadata for a previously opened object as a
dictionary. This is metadata that was written by a POST and does not
include any persistent metadata that was set by the original PUT.
:returns: object\'s .meta file metadata dictionary, or None if there is
no .meta file
:raises DiskFileNotOpen: if the
:func:`swift.obj.diskfile.DiskFile.open` method was not previously
invoked'

def get_metafile_metadata(self):

    if (self._metadata is None):
        raise DiskFileNotOpen()
    return self._metafile_metadata
