Error in ContractObserver: result_handler() takes 1 positional argument but 3 were given

[stiiifff]

When trying to run the Quickstart, and using an ERC20 contract already on-chain (deployed using Redspot), I am getting the following error:

TypeError: result_handler() takes 1 positional argument but 3 were given

To test this, I am using a local Europa instance, and I have previously created, compiled and deployed an ERC20 contract using Redspot, and copied the erc20.json & erc20.wasm files to a res subfolder (as expected by the tutorial code).

Below is the test code:

    substrate=SubstrateInterface(url='ws://127.0.0.1:9944', type_registry_preset="default", type_registry={'types': {'LookupSource': 'MultiAddress'}})

    alice = Keypair.create_from_uri('//Alice')
    bob = Keypair.create_from_uri('//Bob')
    
    erc20_ins = ContractAPI.create_from_address(
        "128vhr5RJeWBnkh36NaMKAE7PP57hkFAYVBGzTAhecvWsnYw",
        os.path.join(os.path.dirname(__file__), 'res', 'erc20.json'),
        substrate
    )
    observer = ContractObserver(erc20_ins.contract_address, erc20_ins.metadata, substrate)

    res = erc20_ins.transfer(alice, bob.ss58_address, 100000, gas_limit=20000000000)
    print('transfer res', res.is_success)

    def on_transfer(num, evt):
        print("on_transfer in {} : {} {} {}".format(num, evt['from'], evt['to'], evt['value']))

    def on_approval(num, evt):
        print("on_approval in {} : {} {} {}".format(num, evt['owner'], evt['spender'], evt['value']))

    observer.scanEvents(handlers={
        'Transfer': on_transfer,
        'Approve': on_approval
    })

[polkadev]

This package have upgrade to v0.3.1, and it contain some examples in https://github.com/patractlabs/py-patract/tree/master/examples/erc20, you can use it for example to test

[stiiifff]

Great thx !