Bootstrap\View\Helper\BootstrapFormHelper::button PHP Method

    public function button($title, array $options = [])
    {
        return $this->_easyIcon('parent::button', $title, $this->_createButtonOptions($options));
    }

 public function button($title, array $options = [])
 {
     if (!isset($options['icon'])) {
         $title = $this->Html->icon('save') . ' ' . $title;
     } else {
         if ($options['icon'] != '') {
             $title = $this->Html->icon($options['icon']) . ' ' . $title;
         }
     }
     return parent::button($title, $options);
 }