'WARNING: if get_cover=True temp files are created for mi.cover.
Remember to delete them once you are done with them.'

def metadata_for(self, ids, get_cover=True):

    ans = []
    for id in ids:
        mi = self.db.get_metadata(id, index_is_id=True, get_cover=get_cover)
        ans.append(mi)
    return ans
