code: def get_username(self):
          
          _from = self.auth_context['from']
          if self.token_version == 1:
              return '{0}'.format(_from)
          elif self.token_version == 2:
              _user_type = self.auth_context['user_type']
              return '{0}/{1}/{2}'.format(
                  self.token_version,
                  _user_type,
                  _from
              )
docs: Get a username formatted for a specific token version.