block.py

import hashlib
import struct

header = {
	"version": 2,
	"prev_block": "000000000000000117c80378b8da0e33559b5997f2ad55e2f7d18ec1975b9717",
	"merkle_root": "871714dcbae6c8193a2bb9b2a69fe1c0440399f38d94b3a0f1b447275a29978a",
	"timestamp": 1392872245,
	"bits": 419520339,
	"nonce": 856192328
}

raw_header = (struct.pack("<L", header["version"]) +
				bytearray.fromhex(header["prev_block"])[::-1] +
				bytearray.fromhex(header["merkle_root"])[::-1] +
				struct.pack("<LLL", header["timestamp"], header["bits"], header["nonce"]))

print(hashlib.sha256(hashlib.sha256(raw_header).digest()).digest()[::-1].hex())