Run yala.

def run(self):
        """Run yala."""
        print('Yala is running. It may take several seconds...')
        try:
            check_call('yala setup.py tests kytos', shell=True)
            print('No linter error found.')
        except CalledProcessError:
            print('Linter check failed. Fix the error(s) above and try again.')
            sys.exit(-1)