src/Request/AlexaRequest.php
public function getSessionValue($key = null)
    {
        return array_key_exists($key, $this->getSession()) ? $this->getSession()[$key] : null;
    }
public function getSessionValue($key = null)
    {
        return array_key_exists($key, $this->getSession()) ? $this->getSession()[$key] : null;
    }
Get a particular session value by key

@param string $key

@return mixed|null