blockchain - ブラウニーを使った交流イベントの聞き取り

Question

私はユニスワップの価格設定を「無限に」リッスンする方法を見つけようとしています。可能であれば、関連するプロジェクトに私をリンクしてください

https://web3py.readthedocs.io/en/stable/filters.html#examples-listening-for-eventsの例を使用しました

しかし、いくつかの変更を加えました

# import the following dependencies
import json
from web3 import Web3
import asyncio
import time

# add your blockchain connection information
infura_url = 'https://eth-kovan.alchemyapi.io/v2/55qP7HQoArbIJEMSfDgdcVEdXOqn_-et'
web3 = Web3(Web3.HTTPProvider(infura_url))

# uniswap address and abi
uniswap_router = '0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D'
uniswap_factory = '0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f'
uniswap_factory_abi = json.loads('[{"inputs":[{"internalType":"address","name":"_feeToSetter","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"token0","type":"address"},{"indexed":true,"internalType":"address","name":"token1","type":"address"},{"indexed":false,"internalType":"address","name":"pair","type":"address"},{"indexed":false,"internalType":"uint256","name":"","type":"uint256"}],"name":"PairCreated","type":"event"},{"constant":true,"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"allPairs","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"allPairsLength","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"tokenA","type":"address"},{"internalType":"address","name":"tokenB","type":"address"}],"name":"createPair","outputs":[{"internalType":"address","name":"pair","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"feeTo","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"feeToSetter","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"getPair","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"_feeTo","type":"address"}],"name":"setFeeTo","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"_feeToSetter","type":"address"}],"name":"setFeeToSetter","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"}]')

contract = web3.eth.contract(address=uniswap_factory, abi=uniswap_factory_abi)
#greeting_Event = contract.events.greeting() # Modification
event_filter = contract.events.PairCreated.createFilter(fromBlock='latest')

# define function to handle events and print to the console
def handle_event(event):
    receipt = web3.eth.waitForTransactionReceipt(event['transactionHash'])
    result = event_filter.processReceipt(receipt) # Modification
    print(result[0]['args'])


# asynchronous defined function to loop
# this loop sets up an event filter and is looking for new entires for the "PairCreated" event
# this loop runs on a poll interval
def log_loop(event_filter, poll_interval):
    while True:
        for event in event_filter.get_new_entries():
            handle_event(event)
            time.sleep(poll_interval)


# when main is called
# create a filter for the latest block and look for the "PairCreated" event for the uniswap factory contract
# run an async loop
# try to run the log_loop function above every 2 seconds
def main():
    event_filter = contract.events.PairCreated.createFilter(fromBlock='latest')
    block_filter = web3.eth.filter({'fromBlock':'latest', 'address':uniswap_factory})
    tx_filter = web3.eth.filter('pending')
    loop = asyncio.get_event_loop()
    try:
        loop.run_until_complete(
            asyncio.gather(
            log_loop(event_filter, 2)
            
            ))
        log_loop(block_filter, 2),
        log_loop(tx_filter, 2)
    finally:
        # close loop to free up system resources
        loop.close()


if __name__ == "__main__":
    main()

これを実行すると、端末が停止するだけです。何が間違っていますか?