Common/View/AbstractView.php
public function addClass($class)
    {
        $classes = $this->getClasses();

        if (!in_array($class, $classes)) {
            $classes[] = $class;
        }

        $this->setClasses($classes);

        return $this;
    }
public function addClass($class)
    {
        $classes = $this->getClasses();

        if (!in_array($class, $classes)) {
            $classes[] = $class;
        }

        $this->setClasses($classes);

        return $this;
    }
Adds the css classes to the view.

@param string $class

@return $this