如何用python编写SIP客户端

import pjsua
import time

# 创建SIP客户端对象
sip = pjsua.Lib()

# 初始化SIP客户端
sip.init(log_cfg=pjsua.LogConfig(level=0, callback=None))

# 设置SIP服务器的地址和端口号
sip_cfg = sip.create_transport(pjsua.TransportType.UDP)
sip_cfg.set_snd_dev(-1)
sip_cfg.set_rcv_dev(-1)
sip_cfg.port = 5060

# 设置SIP客户端的用户名和密码
cred = pjsua.Credentials()
cred.username = 'your_username'
cred.realm = 'your_realm'
cred.scheme = 'digest'
cred.data = 'your_password'

# 添加SIP账户
sip_acc = sip.create_account(sip_cfg, credentials=cred)

# 注册到SIP服务器
sip_acc.set_registration(True)

# 处理SIP事件
while True:
    sip.handle_events()
    time.sleep(0.5)

# 发起呼叫
call = sip_acc.make_call('sip:destination@example.com')

# 接听呼叫
def on_call_state(call):
    if call.info().state == pjsua.CallState.CONFIRMED:
        print('Call answered')
    elif call.info().state == pjsua.CallState.DISCONNECTED:
        print('Call disconnected')

call.set_callback(on_call_state)

# 终止呼叫
call.hangup()