message: Add a more helpful error message to the failure when a decorator identifier could not be resolved.
diff: @@ -53,6 +53,10 @@ class DecoratorsTransformer(converter.Base):
  # This is currently verified by tests.
  continue
  + if not anno.hasanno(dec_func, 'live_val'):
  + raise ValueError('could not resolve the decorator "@%s"' %
  + (anno.getanno(dec_func, anno.Basic.QN)))
  +
  original_dec = anno.getanno(dec_func, anno.Basic.QN)
  dec_value = anno.getanno(dec_func, 'live_val')
  