Getting the ERC20-Token Balance of a Wallet

Hi, I am trying to get the balance of a erc20 token in a wallet but my code seems to be failing. Here's the relevant code:

contract_address = Web3.toChecksumAddress(in_token)
contract_abi = json.loads('[{"inputs":[],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"spender","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"_maxTxAmount","type":"uint256"}],"name":"MaxTxAmountUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"previousOwner","type":"address"},{"indexed":true,"internalType":"address","name":"newOwner","type":"address"}],"name":"OwnershipTransferred","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Transfer","type":"event"},{"inputs":[{"internalType":"address","name":"owner","type":"address"},{"internalType":"address","name":"spender","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"stateMutability":"pure","type":"function"},{"inputs":[{"internalType":"address","name":"notbot","type":"address"}],"name":"delBot","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"manualsend","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"manualswap","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"pure","type":"function"},{"inputs":[],"name":"openTrading","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"owner","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"renounceOwnership","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address[]","name":"bots_","type":"address[]"}],"name":"setBots","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"bool","name":"onoff","type":"bool"}],"name":"setCooldownEnabled","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"pure","type":"function"},{"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"pure","type":"function"},{"inputs":[{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"sender","type":"address"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"stateMutability":"payable","type":"receive"}]')
                                     
def balance_ERC20(ERC20_address):
ERC20_address = Web3.toChecksumAddress(ERC20_address)
contract = web3_connection.eth.contract(address=contract_address, abi=contract_abi)
balance_token = web3_connection.fromWei(contract.functions.balanceOf(ERC20_address).call(), 'ether')
balance_ERC20('self.addr')

The part that's failing: contract_address = Web3.toChecksumAddress(in_token)

The error: when sending a str, it must be a hex string. Got: 'in_token'.

in_token (the token address) is a data that comes from 3rd party so by right it should be detected properly. I tried ' ' for the in_token but still the same result.

Any idea why this is happening?

Thanks in advance guys.

Hello @Tiki

To answer preciselly I would need to see where you call this function, and with what arguments.

However, this is pretty explicit:

Web3.toChecksumAddress expects an hex string. Something like "0x6b175474e89094c44da98b954eedeac495271d0f". Apparently you are giving "in_token", which is not a valid address.