def get_provenance_record(gatt, vatt, ancestor_files):
    """Create a provenance record describing the diagnostic data and plot."""
    caption = ("Ensemble Clustering Diagnostics of extreme {extreme} of "
               .format(**gatt) + "variable {long_name} between "
               "{start_year} and {end_year} ".format(**vatt))
    print(gatt)
    record = {
        'caption': caption,
        'authors': ['hard_jo', 'arno_en', 'mavi_ir'],
        'projects': ['c3s-magic'],
        'references': ['straus07jcli'],
        'plot_types': ['other'],
        'realms': ['atmos'],
        'domains': ['reg'],
        'ancestors': ancestor_files,
    }
    return record