code: def resolve_peer_creds(self):  # LRU cached on per-instance basis
          
          if not IS_UID_GID_RESOLVABLE:
              raise NotImplementedError(
                  'UID/GID lookup is unavailable under current platform. '
                  'It can only be done under UNIX-like OS '
                  'but not under the Google App Engine',
              )
          elif not self.peercreds_resolve_enabled:
              raise RuntimeError(
                  'UID/GID lookup is disabled within this server',
              )
  
          user = pwd.getpwuid(self.peer_uid).pw_name  # [0]
          group = grp.getgrgid(self.peer_gid).gr_name  # [0]
  
          return user, group
docs: Return the username and group tuple of the peercreds if available.
  
          Raises:
              NotImplementedError: in case of unsupported OS
              RuntimeError: in case of UID/GID lookup unsupported or disabled