Web3.py “Unknown account” error when trying to write SmartContract to Pancakeswap router

Question

I started developing a small program which should allow me to buy tokens via pancakeswap router. When I try to do transaction, I get "unknow account" error. I think it might be because I should be locally 'logged' to my metamask account, but it's only my assumption. I exported my private key and tried to make an account from it using w3.eth.account.from_key(privateKey) but it didn't do anything. I also tried to do w3.toChecksumAddress(address) on all addresses but it didn't do anything. I have no idea what can I do at this point.

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This is my code:

 binanceRPC = 'https://bsc-dataseed1.defibit.io/' w3 = Web3(Web3.HTTPProvider(binanceRPC)) PCS_V2_ADDR = w3.toChecksumAddress( '0x10ED43C718714eb63d5aA57B78B54704E256024E') PCS_ABI = #there would be pcs ABI but i needed to delete it due to character limit on stack PCS_ROUTER_CONTRACT = w3.eth.contract(address=PCS_V2_ADDR, abi=PCS_ABI) print(w3.isConnected()) # True WBNB = w3.toChecksumAddress('0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c') shitcoin = w3.toChecksumAddress('0x3ee2200efb3400fabb9aacf31297cbdd1d435d47') nonce = w3.eth.get_transaction_count(testAccAddr) amountIn = 0.0005 tx = { 'nonce': nonce, 'from': testAccAddr, 'to': PCS_V2_ADDR, 'gasPrice': 5, 'gas': 165250, 'value': w3.toWei(amountIn, 'ether') } w3.eth.account.privateKeyToAccount(testAccPrvKey) print(w3.eth.accounts) # [] txHash = PCS_ROUTER_CONTRACT.functions.swapExactETHForTokens(0, [w3.toChecksumAddress('0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c'), w3.toChecksumAddress( '0x3ee2200efb3400fabb9aacf31297cbdd1d435d47')], testAccAddr, 1621289953).transact(tx) # ValueError: {'code': -32000, 'message': 'unknown account'}

Answer 1

Try something like this:

account = w3.eth.account.privateKeyToAccount(testAccPrvKey)
w3.eth.default_account = account.address
txn = PCS_ROUTER_CONTRACT.functions.swapExactETHForTokens(0, 
    [w3.toChecksumAddress('0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c'), 
     w3.toChecksumAddress('0x3ee2200efb3400fabb9aacf31297cbdd1d435d47')], 
     testAccAddr, 1621289953).buildTransaction({
        'chainId': 97, #This is testnet
        'value': w3.toWei(amountIn, 'ether'),
        'nonce': nonce,
    })


signed_txn = account.signTransaction(txn)
txid = w3.toHex(w3.eth.sendRawTransaction(signed_txn.rawTransaction))