public function sizes($sizes = null)
    {

        if ($sizes) {
            $this->sizes = $sizes;

            return $this;
        }

        return empty($this->sizes) ? '100vw' : $this->sizes;
    }
public function sizes($sizes = null)
    {

        if ($sizes) {
            $this->sizes = $sizes;

            return $this;
        }

        return empty($this->sizes) ? '100vw' : $this->sizes;
    }
public function sizes ( $ sizes = null ) { if ( $ sizes ) { $ this -> sizes = $ sizes ; return $ this ; } return empty ( $ this -> sizes ) ? '100vw' : $ this -> sizes ; }
Set or get sizes parameter for srcset media action

@param  string $sizes
@return string
Set or get sizes parameter for srcset media action