Apply theme throughout the network

Recently while working on a project, I was told to apply Twenty Eleven on all the sites in a wordpress network. Instead of hardcoding it, I made a plugin where you could select the theme you want to apply. This is just a one page plugin.

First I made a function which would add the page in the network admin section. This would call another function anshu_apply_theme_settings_form

aes_apply_theme_settings_form function

and the final code of my wordpress plugin was