Simple Ether Transfer on Ropsten

send.py

import web3 
import json
from eth_account import Account
from web3 import Web3
w3 = Web3(Web3.HTTPProvider('https://ropsten.infura.io/v3/apiKey'))
acct = Account.privateKeyToAccount('private key')
nonce = w3.eth.getTransactionCount(acct.address)
transaction = {
    'to' : toAccount,
    'value': 1,
    'gas': 21000,
    'gasPrice': w3.eth.gasPrice,
    'nonce': nonce,
    'chainId': 3
}
key = acct.privateKey
signed = w3.eth.account.signTransaction(transaction, key)
w3.eth.sendRawTransaction(signed.rawTransaction)