code: def stream_header(self, f):
          
          stream_struct("L##L", f, self.version, self.previous_block_hash,
                        self.merkle_root, self.height)
          f.write(b'\0' * 28)
          stream_struct("LL#S", f, self.timestamp, self.difficulty, self.nonce, self.solution)
docs: Stream the block header in the standard way to the file-like object f.