def get_heatmap_df():
    """a simple example to play with and perform test"""
    import pandas as pd
    df = pd.DataFrame({'A': [1, 0, 1, 1], 'B': [0.9, 0.1, 0.6, 1], 'C': [
        0.5, 0.2, 0, 1], 'D': [0.5, 0.2, 0, 1]})
    return df
