Appium使用python进行自动化测试问题，webdriver.Remote编码错误

为了进行app测试，我进行了appium的学习，机器是win7-64位的，环境都已经搭好，下载代码如下：
#coding: utf-8
import os
from time import sleep
from appium import webdriver
# Returns abs path relative to this file and not cwd
PATH = lambda p: os.path.abspath(
os.path.join(os.path.dirname(__file__), p)
)
desired_caps = {}
desired_caps['platformName'] = 'Android'
desired_caps['browserName'] = ''
desired_caps['platformVersion'] = '4.4.2'
desired_caps['appPackage'] = 'com.njzx.lehuoli'
desired_caps['appActivity'] = '.ui.activity.base.MainActivity'
desired_caps['deviceName'] = 'emulator-5554'
driver = webdriver.Remote('http://127.0.0.1:4723/wd/hub/',desired_caps)
el = find_element_by_accessibility_id('com.njzx.lehuoli:id/button_login')
el.click()
time.sleep(5)
driver.quit()
运行以后报错：
Traceback (most recent call last):
File "E:\Workplace\app test\login_test.py", line 22, in <module>
driver = webdriver.Remote('http://127.0.0.1:4723/wd/hub/',desired_caps)
File "E:\Python27\lib\site-packages\appium\webdriver\webdriver.py", line 36, in __init__
super(WebDriver, self).__init__(command_executor, desired_capabilities, browser_profile, proxy, keep_alive)
File "E:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 90, in __init__
self.start_session(desired_capabilities, browser_profile)
File "E:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 177, in start_session
response = self.execute(Command.NEW_SESSION, capabilities)
File "E:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 234, in execute
response = self.command_executor.execute(driver_command, params)
File "E:\Python27\lib\site-packages\selenium\webdriver\remote\remote_connection.py", line 401, in execute
return self._request(command_info[0], url, body=data)
File "E:\Python27\lib\site-packages\selenium\webdriver\remote\remote_connection.py", line 481, in _request
body = data.decode('utf-8').replace('\x00', '').strip()
File "E:\Python27\lib\encodings\utf_8.py", line 16, in decode
return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xb4 in position 193: invalid start byte
哪位大大能帮我看看，好几天了，身为一个菜鸟，真的力不从心了，谢谢！