Get the drupal form

getForm.php

<?php 
 /**
  * Passthrough from Drupal form to the correct condition for building the preview form
  *
  * @param $form
  *   The form array used in hook_form
  * @param $form_state
  *   The form_state array as used in hook_form
  *
  * @return
  *   A drupal form array created but the root condition
  */
  public function getPreviewForm(&$form, &$form_state) {
    $root_condition = $this->getRootCondition();
    function sps_preview_manager_get_condition_form ($form, $form_state) {
      return $root_condition->getElement($form, $form_state);
    }
    return drupal_get_form('sps_preview_manager_get_condition_form');
  }

i was thinking it would be like this
function sps_preview_manager_get_condition_form ($form, $form_state) {
$manager = sps_get_manager();
return $manager->getPreviewForm($form, $form_state)
}