public function set($key, $value, $subject)
    {
        if ($subject === null) {
            $subject = [];
        }

        $subject[$key] = $value;

        return $subject;
    }
public function set($key, $value, $subject)
    {
        if ($subject === null) {
            $subject = [];
        }

        $subject[$key] = $value;

        return $subject;
    }
@param string $key
@param mixed  $value
@param mixed  $subject

@return mixed