Api\StructType\ApiFareItinerary::setKey PHP Method

    public function setKey($key = null)
    {
        // validation for constraint: string
        if (!is_null($key) && !is_string($key)) {
            throw new \InvalidArgumentException(sprintf('Invalid value, please provide a string, "%s" given', gettype($key)), __LINE__);
        }
        $this->key = $key;
        return $this;
    }