def refresh(self):
block = self.blockchain.rpc.get_block_header(self.identifier)<EOL>if not block:<EOL><INDENT>raise BlockDoesNotExistsException<EOL><DEDENT>super(BlockHeader, self).__init__(<EOL>block, blockchain_instance=self.blockchain, use_cache=self._use_cache<EOL>)<EOL>
Even though blocks never change, you freshly obtain its contents
            from an API with this method