http json-rpc error connect to wallet

[SuperCipher]

bchwallet --version bchwallet version 0.9.0
bchd --version bchd version 0.16.3
bchwallet --simnet --noclienttls --noservertls --username admin --password adminpass —rpcconnect localhost:18556

I'm trying to connect to bchwallet through python http post

import getpass
import json
import requests
from requests.auth import HTTPBasicAuth
# python json rpc

# bchd
# URL = "http://127.0.0.1:18556/"

# bchwallet
URL = "http://127.0.0.1:18554/"


def instruct_wallet(method, params):
    payload = json.dumps({"jsonrpc":"1.0","id":"0","method": method, "params": params})
    headers = {'content-type': "application/json", 'cache-control': "no-cache"}
    try:
        response = requests.request("POST", URL, data=payload, headers=headers, auth=HTTPBasicAuth(rpc_user, rpc_password))
        print( json.loads(response.text))
    except requests.exceptions.RequestException as e:
        print (e)
    except:
        print(response)
        # print ('No response from Wallet, check Bitcoin is running on this machine')

rpc_user='admin'
rpc_password='adminpass'

# instruct_wallet('getinfo', [])
instruct_wallet('getbalance', [])

and got this error