code: def _normalize_label(self, s, wsmap):
          
          toks = []
          for tok in list(set(self.npattern.sub(' ', s).split(' '))):
              if tok in wsmap:
                  tok=wsmap[tok]
              if tok != "":
                  toks.append(tok)
          toks.sort()
          return " ".join(toks)
docs: normalized form of a synonym