Hooking in Sensei wrappers for Twenty Ten

gistfile1.php

add_action('sensei_before_main_content', 'my_theme_wrapper_start', 10);
add_action('sensei_after_main_content', 'my_theme_wrapper_end', 10);

function my_theme_wrapper_start() {
  echo '<div id="container"><div id="content" role="main">';
}

function my_theme_wrapper_end() {
  echo '</div><!-- #content -->
	</div><!-- #container -->';
	get_sidebar();
}

This would make a lot of more sense if you could make real example on how to do it. All that I can understand from this is to replace ''my_theme_wrapper_start'' my_theme_wrapper_end' with something from the themes page.php. But with what?
I would understand it if you could show a real example with 1 or 2 themes.