def check_configuration_tokens(self):
        '''Ensure the spec file is 'correct'.
        '''
        self.info('Check configuration tokens')
        get = self.config.getdefault
        errors = []
        adderror = errors.append
        if not get('app', 'title', ''):
            adderror('[app] "title" is missing')
        if not get('app', 'source.dir', ''):
            adderror('[app] "source.dir" is missing')

        package_name = get('app', 'package.name', '')
        if not package_name:
            adderror('[app] "package.name" is missing')
        elif package_name[0] in map(str, range(10)):
            adderror('[app] "package.name" may not start with a number.')

        version = get('app', 'version', '')
        version_regex = get('app', 'version.regex', '')
        if not version and not version_regex:
            adderror('[app] One of "version" or "version.regex" must be set')
        if version and version_regex:
            adderror('[app] Conflict between "version" and "version.regex"'
                    ', only one can be used.')
        if version_regex and not get('app', 'version.filename', ''):
            adderror('[app] "version.filename" is missing'
                ', required by "version.regex"')

        orientation = get('app', 'orientation', 'landscape')
        if ('landscape', 'portrait', 'all') not in orientation:
            adderror('[app] "orientation" have an invalid value')

        if errors:
            self.error('{0} error(s) found in the buildozer.spec'.format(
                len(errors)))
            for error in errors:
                print(error)
            exit(1)
dataset/ETHPy150Open kivy/buildozer/buildozer/__init__.py/Buildozer.check_configuration_tokens/swapped operands of `not in`