public function set($index, $value = null)
    {
        if (is_array($index)) {
            $this->data = array_merge($this->data, $index);
        } else {
            $this->data[$index] = $value;
        }
        return $this;
    }
public function set($index, $value = null)
    {
        if (is_array($index)) {
            $this->data = array_merge($this->data, $index);
        } else {
            $this->data[$index] = $value;
        }
        return $this;
    }
public function set ( $ index , $ value = null ) { if ( is_array ( $ index ) ) { $ this -> data = array_merge ( $ this -> data , $ index ) ; } else { $ this -> data [ $ index ] = $ value ; } return $ this ; }
Set a single property or multiple properties at once

@param string|array $index
@param mixed $value
Set a single property or multiple properties at once