How to set certain custom order on x variables in seaborn plots?

Question

For example I have am plotting box plots this way :-

plt.figure(figsize=(8,5))
sns.boxplot(x='class',y='age',data=titanic, palette='rainbow')
plt.title("Age by Passenger Class, Titanic")

I want to set the order of class like Thrid class,First class ,Second Class from left to right on the box plots then what should I do?

NOTE : Tried hue_order but I find no difference in the results