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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 get_sls_config_file(path, stage, region):
 """Determine Serverless config file name."""

    for name in gen_sls_config_files(stage, region):
        if os.path.isfile(os.path.join(path, name)):
            return name
    return "config-%s.json" % stage