protected function assertConfigIsValid(): void
    {
        foreach ($this->configProperties as $property) {
            if (empty(self::$config[$this->configSectionName][$property])) {
                throw new InvalidConfigException(
                    sprintf(
                        "Config section does not exist or is not filled properly: %s (\"%s\" is missing)",
                        $this->configSectionName,
                        $property
                    )
                );
            }
        }

        $this->assertApiClassImplementsInterface($this->apiInterface);
    }