django使用forms表单报错报错 '*Form' object has no attribute 'cleaned_data

'*Form' object has no attribute 'cleaned_data'

django进行forms开发时报错
'LoginForm' object has no attribute 'cleaned_data'

但是实际上这个方法是存在的，后来发现.is_valid()方法的括号给遗漏掉了，后来加上就好了
if form.is_valid():
cd = form.cleaned_data

参考：https://www.iteye.com/blog/msq-1714831