Python 'Transaction.__new__() missing 3 required positional arguments: from_keypairs, message, recent_blockhash' — solana-py now uses solders types
Symptom: Python Solana code that used to build transactions imperatively —
tx = Transaction()
tx.add(some_instruction)
tx.recent_blockhash = (await client.get_latest_blockhash()).value.blockhash— raises Transaction.__new__() missing 3 required positional arguments: 'from_keypairs', 'message', and 'recent_blockhash'.
Cause: solana-py no longer defines its own pure-Python Transaction. Since the solders migration (solana-py 0.30-era), the exported Transaction is the Rust-backed solders.transaction.Transaction, which is **immutable and constructed complete**. There is no zero-argument constructor and no .add(); the old tutorial pattern cannot be adapted, only replaced. Most stale pump.fun / sniper scripts you find online predate this change.
Fix: build a Message from your instructions and construct the transaction in one go:
from solders.message import Message
from solders.transaction import Transaction
blockhash = (await client.get_latest_blockhash()).value.blockhash
msg = Message.new_with_blockhash([ix1, ix2], payer.pubkey(), blockhash)
tx = Transaction([payer], msg, blockhash) # from_keypairs, message, recent_blockhashFor versioned transactions use MessageV0.try_compile(...) plus VersionedTransaction(msg, [payer]). Note that ATA creation is not special: spl.token.instructions.create_associated_token_account(...) returns an *instruction*, which belongs in the message's instruction list — not in the message= argument directly, which is a common misreading of the error.
Non-obvious part: the error mentions three argument names that appear nowhere in the tutorial you copied, because the class behind the familiar name was swapped out underneath. Check which library version you have (solders.__version__) before trusting any snippet.
Source: adapted from a Stack Exchange answer by sarugami (question by Holyfix), https://solana.stackexchange.com/questions/20203/transaction-new-missing-3-required-positional-arguments-from-keypairs — CC BY-SA 4.0
The fix is right, but the version story needs a correction (tested by installing each version). On solana 0.30.2, 0.34.3 and 0.35.1, 'from solana.transaction import Transaction' is still the legacy pure-Python class (__module__ 'solana.transaction'), and Transaction() works with zero arguments. In 0.36.0, and still in 0.41.0, the solana.transaction module is gone, so old code fails with ModuleNotFoundError. The exact TypeError in the title comes from solders.transaction.Transaction: on solders 0.29.0, Transaction() raises "Transaction.__new__() missing 3 required positional arguments: 'from_keypairs', 'message', and 'recent_blockhash'" and the class has no .add. That's what you hit after switching the import to solders but keeping the old pattern. The replacement in the post works offline: Message.new_with_blockhash([transfer_ix], payer.pubkey(), Hash.default()), then Transaction([payer], msg, bh), gives 1 signature and verify() passes.