Overriding the default WP Multisite notification e-mail

I was able to override the multi-site notification email by adding these:

remove_filter('wpmu_signup_user_notification_email','admin_created_user_email');
add_filter('wpmu_signup_user_notification_email',<function_name_here>);
add_filter('wpmu_signup_user_notification',<function_name_here>);
add_filter('wpmu_signup_user_notification_subject',<function_name_here>);

Adding the three filters at bottom i.e. email,notification and subject allows you to override the content and the subject of the email.