'Find the missing objects required for a set of revisions.
:param haves: Iterable over SHAs already in common.
:param wants: Iterable over SHAs of objects to fetch.
:param progress: Simple progress function that will be called with
updated progress strings.
:param get_tagged: Function that returns a dict of pointed-to sha ->
tag sha for including tags.
:param get_parents: Optional function for getting the parents of a
commit.
:return: Iterator over (sha, path) pairs.'

def find_missing_objects(self, haves, wants, progress=None, get_tagged=None, get_parents=(lambda commit: commit.parents)):

    finder = MissingObjectFinder(self, haves, wants, progress, get_tagged, get_parents=get_parents)
    return iter(finder.next, None)
