"""
# tag::example1[]
>>> from tx import Tx
>>> from io import BytesIO
>>> raw_tx = ('0100000001813f79011acb80925dfe69b3def355fe914bd1d96a3f5f71bf830\
3c6a989c7d1000000006b483045022100ed81ff192e75a3fd2304004dcadb746fa5e24c5031ccf\
cf21320b0277457c98f02207a986d955c6e0cb35d446a89d3f56100f4d7f67801c31967743a9c8\
e10615bed01210349fc4e631e3624a545de3f89f5d8684c7b8138bd94bdd531d2e213bf016b278\
afeffffff02a135ef01000000001976a914bc3b654dca7e56b04dca18f2566cdaf02e8d9ada88a\
c99c39800000000001976a9141c4bc762dd5423e332166702cb75f40df79fea1288ac19430600')
>>> stream = BytesIO(bytes.fromhex(raw_tx))
>>> transaction = Tx.parse(stream)
>>> print(transaction.fee() >= 0)  # <1>
True

# end::example1[]
# tag::example2[]
>>> from ecc import S256Point, Signature
>>> sec = bytes.fromhex('0349fc4e631e3624a545de3f89f5d8684c7b8138bd94bdd531d2e\
213bf016b278a')
>>> der = bytes.fromhex('3045022100ed81ff192e75a3fd2304004dcadb746fa5e24c5031c\
cfcf21320b0277457c98f02207a986d955c6e0cb35d446a89d3f56100f4d7f67801c31967743a9\
c8e10615bed')
>>> z = 0x27e0c5994dec7824e56dec6b2fcb342eb7cdb0d0957c2fce9882f715e85d81a6
>>> point = S256Point.parse(sec)
>>> signature = Signature.parse(der)
>>> print(point.verify(z, signature))
True

# end::example2[]
# tag::example3[]
>>> from helper import hash256
>>> modified_tx = bytes.fromhex('0100000001813f79011acb80925dfe69b3def355fe914\
bd1d96a3f5f71bf8303c6a989c7d1000000001976a914a802fc56c704ce87c42d7c92eb75e7896\
bdc41ae88acfeffffff02a135ef01000000001976a914bc3b654dca7e56b04dca18f2566cdaf02\
e8d9ada88ac99c39800000000001976a9141c4bc762dd5423e332166702cb75f40df79fea1288a\
c1943060001000000')
>>> h256 = hash256(modified_tx)
>>> z = int.from_bytes(h256, 'big')
>>> print(hex(z))
0x27e0c5994dec7824e56dec6b2fcb342eb7cdb0d0957c2fce9882f715e85d81a6

# end::example3[]
# tag::example4[]
>>> from ecc import S256Point, Signature
>>> sec = bytes.fromhex('0349fc4e631e3624a545de3f89f5d8684c7b8138bd94bdd531d2e\
213bf016b278a')
>>> der = bytes.fromhex('3045022100ed81ff192e75a3fd2304004dcadb746fa5e24c5031c\
cfcf21320b0277457c98f02207a986d955c6e0cb35d446a89d3f56100f4d7f67801c31967743a9\
c8e10615bed')
>>> z = 0x27e0c5994dec7824e56dec6b2fcb342eb7cdb0d0957c2fce9882f715e85d81a6
>>> point = S256Point.parse(sec)
>>> signature = Signature.parse(der)
>>> point.verify(z, signature)
True

# end::example4[]
# tag::example5[]
>>> from helper import decode_base58, SIGHASH_ALL
>>> from script import p2pkh_script, Script
>>> from tx import TxIn, TxOut, Tx
>>> prev_tx = bytes.fromhex('0d6fe5213c0b3291f208cba8bfb59b7476dffacc4e5cb66f6\
eb20a080843a299')
>>> prev_index = 13
>>> tx_in = TxIn(prev_tx, prev_index)
>>> tx_outs = []
>>> change_amount = int(0.33*100000000)  # <1>
>>> change_h160 = decode_base58('mzx5YhAH9kNHtcN481u6WkjeHjYtVeKVh2')
>>> change_script = p2pkh_script(change_h160)
>>> change_output = TxOut(amount=change_amount, script_pubkey=change_script)
>>> target_amount = int(0.1*100000000)  # <1>
>>> target_h160 = decode_base58('mnrVtF8DWjMu839VW3rBfgYaAfKk8983Xf')
>>> target_script = p2pkh_script(target_h160)
>>> target_output = TxOut(amount=target_amount, script_pubkey=target_script)
>>> tx_obj = Tx(1, [tx_in], [change_output, target_output], 0, True)  # <2>
>>> print(tx_obj)
tx: cd30a8da777d28ef0e61efe68a9f7c559c1d3e5bcd7b265c850ccb4068598d11
version: 1
tx_ins:
0d6fe5213c0b3291f208cba8bfb59b7476dffacc4e5cb66f6eb20a080843a299:13
tx_outs:
33000000:OP_DUP OP_HASH160 d52ad7ca9b3d096a38e752c2018e6fbc40cdf26f OP_EQUALVE\
RIFY OP_CHECKSIG
10000000:OP_DUP OP_HASH160 507b27411ccf7f16f10297de6cef3f291623eddf OP_EQUALVE\
RIFY OP_CHECKSIG
locktime: 0

# end::example5[]
# tag::example6[]
>>> from ecc import PrivateKey
>>> from helper import SIGHASH_ALL
>>> z = transaction.sig_hash(0)  # <1>
>>> private_key = PrivateKey(secret=8675309)
>>> der = private_key.sign(z).der()
>>> sig = der + SIGHASH_ALL.to_bytes(1, 'big')  # <2>
>>> sec = private_key.point.sec()
>>> script_sig = Script([sig, sec])  # <3>
>>> transaction.tx_ins[0].script_sig = script_sig   # <4>
>>> print(transaction.serialize().hex())
0100000001813f79011acb80925dfe69b3def355fe914bd1d96a3f5f71bf8303c6a989c7d10000\
00006a47304402207db2402a3311a3b845b038885e3dd889c08126a8570f26a844e3e4049c482a\
11022010178cdca4129eacbeab7c44648bf5ac1f9cac217cd609d216ec2ebc8d242c0a01210393\
5581e52c354cd2f484fe8ed83af7a3097005b2f9c60bff71d35bd795f54b67feffffff02a135ef\
01000000001976a914bc3b654dca7e56b04dca18f2566cdaf02e8d9ada88ac99c3980000000000\
1976a9141c4bc762dd5423e332166702cb75f40df79fea1288ac19430600

# end::example6[]
# tag::example7[]
>>> from ecc import PrivateKey
>>> from helper import hash256, little_endian_to_int
>>> secret = little_endian_to_int(hash256(b'Jimmy Song secret'))  # <1>
>>> private_key = PrivateKey(secret)
>>> print(private_key.point.address(testnet=True))
mn81594PzKZa9K3Jyy1ushpuEzrnTnxhVg

# end::example7[]
"""