def filter_df_on_contamination(in_df):
    """Get a df or string of the genome id with the lowest contamination"""
    min_contamination = in_df.contamination.min()
    on_contamination = in_df.loc[
        in_df.contamination == min_contamination,
    ]
    if on_contamination.shape[0] == 1:
        return on_contamination.genome_id.values[0]
    else:
        return on_contamination