code: def get_keep_score(source_counts, prediction_counts, target_counts):
    
    source_and_prediction_counts = source_counts & prediction_counts
    source_and_target_counts = source_counts & target_counts
    true_positives = sum((source_and_prediction_counts &
                          source_and_target_counts).values())
    selected = sum(source_and_prediction_counts.values())
    relevant = sum(source_and_target_counts.values())
    return _get_fbeta_score(true_positives, selected, relevant)
docs: Compute the keep score (Equation 5 in the paper).