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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def settings(instance):
 """Definition to set settings from config file to the app instance."""

    with open(instance.root_dir + '/Config/config.yml') as config:
        config = yaml.load(config)
        instance.name = config['name']
        instance.port = config['web']['port']
        # default host
        instance.host = "http://localhost"
        if 'host' in config['web']:
            instance.host = config['web']['host']
        instance.debug = config['debug']
    return instance