code: def ustr(x):
      """py2/py3 unicode helper"""
  
      if sys.version_info < (3, 0, 0):
          from PyQt4.QtCore import QString
  
          if type(x) == str:
              return x.decode(DEFAULT_ENCODING)
          if type(x) == QString:
              # https://blog.csdn.net/friendan/article/details/51088476
              # https://blog.csdn.net/xxm524/article/details/74937308
              return unicode(x.toUtf8(), DEFAULT_ENCODING, "ignore")
          return x
      else:
          return x
  
label_desc: Use image node_id 1 for calling a global function with example usage: ustr(x) and returns: x, x, x, unicode