code: def safe_tag(self, tag, errors='strict'):
          
          if tag is not None:
              try:
                  # handle unicode characters and url encode tag value
                  tag = quote(self.s(tag, errors=errors), safe='~')[:128]
              except KeyError as e:
                  warn = 'Failed converting tag to safetag ({})'.format(e)
                  self.log.warning(warn)
          return tag
docs: URL Encode and truncate tag to match limit (128 characters) of ThreatConnect API.
  
          Args:
             tag (string): The tag to be truncated
  
          Returns:
              (string): The truncated tag