def metadata2csv(dataset, fname, **kwargs):
    """Writes metadata to CSV-file.
    
    With this function, you can write metadata 
    
    Args:
        datamodel (pd.DataFrame): A pandas DataFrame containing metadata, where
            each row stands for one document.
        fname (str): Filename for CSV-file.
    
    Returns:
        None
    """
    dataset.to_csv(fname, **kwargs)
