code: def _serialize_hcons(hcons):
      
      toks = ['HCONS:', '<']
      for hc in hcons:
          toks.extend(hc)
          # reln = hcon[1]
          # toks += [hcon[0], rel, str(hcon.lo)]
      toks += ['>']
      return ' '.join(toks)
docs: Serialize [HandleConstraints] into the SimpleMRS encoding.