SyntaxError：帶有契約 ABI 的 web.py 上的語法無效

大家，每次我嘗試在從 Remix IDE 獲得的contract_abi變數上執行此腳本時，我都會遇到**SyntaxError: invalid syntax的問題。**我目前正在嘗試連接 Ropsten 測試網中的智能合約並簡單地呼叫視圖函式。這是我的程式碼：

import argparse
import sys
import time
import RPi.GPIO as GPIO
from web3 import Web3, HTTPProvider
from chirp import ChirpConnect, CallbackSet, CHIRP_CONNECT_STATE

contract_address = '0xf9bd6f5382f841f8ec9ac1a2b0576c55e45db051'
wallet_private_key = '54485fb890521bbf8345b39dd78aa4f6e02abd9a57e172bc894ded3401d42b07'
wallet_address = '0x5a6e5c4cc373a45ec2c1fe0cf41ff75c6cf930b8'

web3 = Web3(HTTPProvider('https://mainnet.infura.io/v3/a222429a84da4e95bb6d2f16f675d00b')

contract_abi = '''
[
   {
       "constant": true,
       "inputs": [],
       "name": "getKey",
       "outputs": [
           {
               "name": "",
               "type": "string"
           }
       ],
       "payable": false,
       "stateMutability": "view",
       "type": "function"
   },
   {
       "inputs": [
           {
               "name": "_key",
               "type": "string"
           }
       ],
       "payable": false,
       "stateMutability": "nonpayable",
       "type": "constructor"
   }
]
'''

contract_instance = web3.eth.contract(address = contract_address, abi = contract_abi)

class MyCallbacks(CallbackSet):

   def on_state_changed(self, previous_state, current_state):
       """ Called when the SDK's state has changed """
       print("State changed from {} to {}".format(
           CHIRP_CONNECT_STATE.get(previous_state),
           CHIRP_CONNECT_STATE.get(current_state)))

   def on_sending(self, payload):
       """ Called when a chirp has started to be transmitted """
       print('Sending: ' + str(payload))

   def on_sent(self, payload):
       """ Called when the entire chirp has been sent """
       print('Sent data')

   def on_receiving(self):
       """ Called when a chirp frontdoor is detected """
       print('Receiving data')

   def on_received(self, payload):
       """
       Called when an entire chirp has been received.
       Note: A length of 0 indicates a failed decode.
       """
       if len(payload) == 0:
           print('Decode failed!')
       else:
           print('Received:' + str(payload))
           print(contract_instance.functions.getKey().call())    


def main(app_key, app_secret, licence_file,
        input_device, output_device,
        block_size, sample_rate):

   # Initialise ConnectSDK
   sdk = ChirpConnect(app_key, app_secret, licence_file)
   print(str(sdk))
   print(sdk.audio.query_devices())

   # Configure audio
   sdk.audio.input_device = input_device
   sdk.audio.output_device = output_device
   sdk.audio.block_size = block_size
   sdk.sample_rate = sample_rate

   # Set callback functions
   sdk.set_callbacks(MyCallbacks())

   # Generate random payload and send
   payload = sdk.random_payload()
   sdk.start(send=True, receive=True)
   sdk.send(payload)

   try:
       # Process audio streams
       while True:
           time.sleep(0.1)
           sys.stdout.write('.')
           sys.stdout.flush()
   except KeyboardInterrupt:
       print('Exiting')

   sdk.stop()
   sdk.close()


if __name__ == '__main__':
   parser = argparse.ArgumentParser(
       description='Chirp Connect SDK Example',
       epilog='Sends a random chirp payload, then continuously listens for chirps'
   )
   parser.add_argument('key', help='Chirp application key')
   parser.add_argument('secret', help='Chirp application secret')
   parser.add_argument('-l', help='Path to licence file (optional)')
   parser.add_argument('-i', type=int, default=None, help='Input device index (optional)')
   parser.add_argument('-o', type=int, default=None, help='Output device index (optional)')
   parser.add_argument('-b', type=int, default=0, help='Block size (optional)')
   parser.add_argument('-s', type=int, default=44100, help='Sample rate (optional)')
   args = parser.parse_args()

   main(args.key, args.secret, args.l, args.i, args.o, args.b, args.s)

我在 Ropsten 上部署的智能合約是這樣的：

pragma solidity ^0.4.19;

contract SimpleTest {

   string key;

   constructor (string _key) {
       key = _key;
   }

   function getKey() public view returns(string) {
       return key;
   }

}

有誰知道我做錯了什麼？提前致謝！

該web3 = ...行缺少尾隨括號。

引用自：https://ethereum.stackexchange.com/questions/58933