Python+selenium for IFRAME cut-out

Found the problem: when the http://www.126.com automated test login mailbox, always can not locate the login name and password. No matter how to use CLASS,XPATH,ID,CSS, etc. are not. After careful review, only to find this landing embedded, that is, the IFRAME, so you have to cut in order to locate the element up.
Workaround:

1. First, for the embedded HTML of the IFRAME, use Switch_to.frame to cut into the IFRAME to get the elements.
2. When you want to get an IFRAME external element, use Switch_to_default_content () to cut out the IFRAME. If you do not cut out, printing with print will report a "dead object" error because the IFRAME has not been cut out.

Python+selenium for IFRAME cut-out