Painless collapsible content in Drupal

How to create collapsible content in Drupal? It is easy! No, it really is. No more annoying additional render arrays with '#collapsible' => TRUE.  Just look at this trick! It is brilliant!

Example 1: Using theme() function

print theme('ctools_collapsible',
    'handle' => 'Click me and you will see collapsed content',
    'content' => $collapsed_content,
    'collapsed' => TRUE

Example 2: Using in render arrays

$collapsed_content = array(
  '#markup' => t('No! Hide me! Hurry, i`m shy!'),

$render = array();
$render['collapsible'] = array(
  '#theme' => 'ctools_collapsible',
  '#handle' => t('Click me and you will see collapsed content'),
  '#collapsed' => TRUE,
  '#content' => drupal_render($collapsed_content),

print drupal_render($render);