code: def obfuscate(cls, idStr):
          
          return unicode(base64.urlsafe_b64encode(
              idStr.encode('utf-8')).replace(b'=', b''))
docs: Mildly obfuscates the specified ID string in an easily reversible
          fashion. This is not intended for security purposes, but rather to
          dissuade users from depending on our internal ID structures.