function add($value) {
        if(!\in_array($value, $this->data, true)) {
            $this->data[] = $value;
        }
        
        return $this;
    }
function add($value) {
        if(!\in_array($value, $this->data, true)) {
            $this->data[] = $value;
        }
        
        return $this;
    }
function add ( $ value ) { if ( ! \ in_array ( $ value , $ this -> data , true ) ) { $ this -> data [ ] = $ value ; } return $ this ; }
Adds a value to the Set.
@param mixed  $value
@return $this
Adds a value to the Set .