code: def beholder(func):
      
      @functools.wraps(func)
      def behold(self, proto, length, *args, **kwargs):
          seek_cur = self._file.tell()
          try:
              return func(proto, length, *args, **kwargs)
          except Exception:
              from pcapkit.protocols.raw import Raw
              error = traceback.format_exc(limit=1).strip().split(os.linesep)[-1]
              # error = traceback.format_exc()
  
              self._file.seek(seek_cur, os.SEEK_SET)
              next_ = Raw(io.BytesIO(self._read_fileng(length)), length, error=error)
              return next_
      return behold
docs: [ClassMethod] Behold extraction procedure.