Pycoin does not validate Gavin Andresen's test multisig transaction (https://gist.github.com/gavinandresen/3966071)

837dea.py

#! /usr/bin/python3

import sys
from pycoin.tx import Tx, TxIn, TxOut
from pycoin.tx.Tx import SIGHASH_ALL
from pycoin.key import Key
from pycoin.tx.script.vm import parse_signature_blob
from pycoin.encoding import *
from pycoin.serialize import *

# Gavin Andresen's multisig test
# https://gist.github.com/gavinandresen/3966071

# tx0 = funding  tx, id: 3c9018e8d5615c306d72397f8f5eef44308c98fb576a88e030c25456b4f3a7ac
# url: https://blockchain.info/rawtx/3c9018e8d5615c306d72397f8f5eef44308c98fb576a88e030c25456b4f3a7ac?format=hex
# tx1 = spending tx, id: 837dea37ddc8b1e3ce646f1a656e79bbd8cc7f558ac56a169626d649ebe2a3ba
# url: https://blockchain.info/rawtx/837dea37ddc8b1e3ce646f1a656e79bbd8cc7f558ac56a169626d649ebe2a3ba?format=hex

tx_HEX = [ 
'010000000189632848f99722915727c5c75da8db2dbf194342a0429828f66ff88fab2af7d6000000008b483045022100abbc8a73fe2054480bda3f3281da2d0c51e2841391abd4c09f4f908a2034c18d02205bc9e4d68eafb918f3e9662338647a4419c0de1a650ab8983f1d216e2a31d8e30141046f55d7adeff6011c7eac294fe540c57830be80e9355c83869c9260a4b8bf4767a66bacbd70b804dc63d5beeb14180292ad7f3b083372b1d02d7a37dd97ff5c9effffffff0140420f000000000017a914f815b036d9bbbce5e9f2a00abd1bf3dc91e955108700000000',
'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'
]

tx_LIST=[Tx.tx_from_hex(tx) for tx in tx_HEX]
tx_DB=dict((tx.hash(), tx) for tx in tx_LIST)

tx1 = tx_LIST[1]
print("# tx1.as_hex():\n%s" % tx1.as_hex())

tx1.unspents_from_db(tx_DB)
if not tx1.is_signature_ok(0):
    print("# tx1.is_signature_ok(0): False. That's bad.")
else:
    print("OK.")
    sys.exit(0)

print("# Try to regenerate the transaction.")

# Private keys
priv_keys = \
    ['5JaTXbAUmfPYZFRwrYaALK48fN6sFJp4rHqq2QSXs8ucfpE4yQU',
     '5JFjmGo5Fww9p8gvx48qBYDJNAzR9pmH5S389axMtDyPT8ddqmw',
     '5Jb7fCeh1Wtm4yBBg3q3XbT6B525i17kVhy3vMC9AqfR6FH2qGk'
     ]

keys = [ Key.from_text(s) for s in priv_keys]

# Raw, unsigned transaction from Gavin's gist.
tx_tmp=Tx.tx_from_hex('0100000001aca7f3b45654c230e0886a57fb988c3044ef5e8f7f39726d305c61d5e818903c0000000000ffffffff0140420f00000000001976a914ae56b4db13554d321c402db3961187aed1bbed5b88ac00000000')
redeem_script=h2b('52410491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f864104865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a986818a7cb624532f062c1d1f8722084861c5c3291ccffef4ec687441048d2455d2403e08708fc1f556002f1b6cd83f992d085097f9974ab08a28838f07896fbab08f39495e15fa6fad6edbfb1e754e35fa1c7844c41f322a1863d4621353ae')
p2sh_lookup = {hash160(redeem_script): redeem_script}

# Construct hash160_lookup dictionary for two keys Gavin used to sign his transaction
hash160_lookup= {k.hash160(): (k.secret_exponent(), k.public_pair(), True) for k in keys[:-1]}

tx_tmp.unspents_from_db(tx_DB)
tx_tmp.sign(hash160_lookup, hash_type=SIGHASH_ALL, p2sh_lookup=p2sh_lookup)

print("# tx_tmp.as_hex():\n%s" % tx_tmp.as_hex())

if tx_tmp.is_signature_ok(0):
    print("# tx_tmp.is_signature_ok(0): True")