问appium+python app 自动化测试？

Traceback (most recent call last):

File "/Users/mac/PycharmProjects/untitled/wt.py", line 23, in <module>

driver = webdriver.Remote("http://127.0.0.1:4723/wd/hub",desired_caps)

File "/Users/mac/PycharmProjects/untitled/venv/lib/python3.6/site-packages/appium/webdriver/webdriver.py", line 144, in __init__

proxy

File "/Users/mac/PycharmProjects/untitled/venv/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 157, in __init__

self.start_session(capabilities, browser_profile)

File "/Users/mac/PycharmProjects/untitled/venv/lib/python3.6/site-packages/appium/webdriver/webdriver.py", line 219, in start_session

response = self.execute(RemoteCommand.NEW_SESSION, parameters)

File "/Users/mac/PycharmProjects/untitled/venv/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 321, in execute

self.error_handler.check_response(response)

File "/Users/mac/PycharmProjects/untitled/venv/lib/python3.6/site-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response

raise exception_class(message, screen, stacktrace)

selenium.common.exceptions.WebDriverException: Message: An unknown server-side error occurred while processing the command. Original error: You must include a platformName capability

以上是pycharm的所有报错信息，求大神指点