private function setProject(InputInterface $input, OutputInterface $output)
    {
        $this->project = $input->getOption('projectname');
        if (!$this->project) {
            $this->project = $this->getTransifexConfigValue('/project');

            if (!$this->project) {
                throw new \RuntimeException('Error: unable to determine transifex project name.');
            }

            $this->writelnVerbose($output, sprintf('<info>automatically using project: %s</info>', $this->project));
        }

        $this->checkValidSlug($this->project);
    }