how to make boxplot map grouped by target

Question

I could not code a boxplot with price value, it's all the same that price has 0 value? How to fix this?

for col in categorical_features:
fig = plt.figure(figsize=(9, 6))
ax = fig.gca()
df.boxplot (column = 'price', by = col, ax = ax)
ax.set_title('Label by ' + col)
ax.set_ylabel("Price")```

code above could not return map with data grouped by price

please help to make boxplot make sense