def _check(self, val):
if not isinstance(val, Chunk):<EOL><INDENT>raise TypeError<EOL><DEDENT>
Checks if the value is an instance of :obj:`budou.chunk.Chunk`.

        Args:
          val (:obj:`budou.chunk.Chunk`): input to check

        Raises:
          TypeError: If :code:`val` is not an instance of :obj:`budou.chunk.Chunk`.