def __init__(self, config, archiver):
self.config = config<EOL>self.archiver = archiver<EOL>self.data = (<EOL>cache.get_archiver_index(config, archiver.name)<EOL>if cache.has_archiver_index(config, archiver.name)<EOL>else []<EOL>)<EOL>self._revisions = OrderedDict()<EOL>for d in self.data:<EOL><INDENT>self._revisions[d["<STR_LIT:key>"]] = IndexedRevision.fromdict(d)<EOL><DEDENT>
Instantiate a new index.

:param config: The wily config.
:type  config: :class:`wily.config.WilyConfig`

:param archiver: The archiver.
:type  archiver: :class:`wily.archivers.Archiver`