/**
  * Drop all tasks that are in this list
  *
  * @access public
  * @param void
  * @return boolean
  */
 function deleteHandins()
 {
     $q = DB::escapeField('rel_object_id') . ' = ' . DB::escape($this->getId()) . ' AND ' . DB::escapeField('rel_object_manager') . ' = ' . DB::escape(get_class($this->manager()));
     return ObjectHandins::delete($q);
 }