[Plugin: Allow PHP in Posts and Pages] The proper syntax for the shortcode

I am writing it this way. Is this correct because my page is blank and getting no errors.
[php][php function=1][/php]

I also tried [php function=1]

In the code snippet box I left off the <?php
It says all snippets automatically start with <?php so not sure what needs to be in the box. Do I need to use the title?

http://wordpress.org/extend/plugins/allow-php-in-posts-and-pages/