code: def _qname(self, name):
          
          if isinstance(name, QName):
              return name
          if not isinstance(name, str):
              raise TypeError("{} must be str".format(name))
          if name == '':
              return name
          if name.startswith('{'):
              return name
          prefix, tag = name.split(':', maxsplit=1)
          uri = self.NS[prefix]
          return QName(uri, tag)
docs: Convert name to an XML QName
  
          e.g. pdf:Producer -> {http://ns.adobe.com/pdf/1.3/}Producer