'Augment the LU information that was loaded from the frame file
with additional information from the LU file.'

def _lu_file(self, lu, ignorekeys=[]):

    fn_luid = lu.ID
    fname = u'lu{0}.xml'.format(fn_luid)
    locpath = os.path.join(u'{0}'.format(self._root), self._lu_dir, fname)
    if (not self._lu_idx):
        self._buildluindex()
    try:
        elt = XMLCorpusView(locpath, u'lexUnit')[0]
    except IOError:
        raise FramenetError(u'Unknown    LU    id:    {0}'.format(fn_luid))
    lu2 = self._handle_lexunit_elt(elt, ignorekeys)
    lu.URL = ((((self._fnweb_url + u'/') + self._lu_dir) + u'/') + fname)
    lu.subCorpus = lu2.subCorpus
    lu.exemplars = SpecialList(u'luexemplars', [sent for subc in lu.subCorpus for sent in subc.sentence])
    for sent in lu.exemplars:
        sent[u'LU'] = lu
        sent[u'frame'] = lu.frame
        for aset in sent.annotationSet:
            aset[u'LU'] = lu
            aset[u'frame'] = lu.frame
    return lu
