age_list = [8, 10, 12, 14, 72, 74, 76, 78, 20, 25, 30, 35, 60, 85]  # doctest: +SKIP
df = pd.DataFrame({"gender": list("MMMMMMMMFFFFFF"), "age": age_list})  # doctest: +SKIP
ax = df.plot.box(column="age", by="gender", figsize=(10, 8))  # doctest: +SKIP