I have a dataframe containing a column called bmi (Body Mass Index) containing int values

![enter image description here](https://i.stack.imgur.com/xgPOA.png)

I have to separate the values in bmi column into Under weight, Normal, Over weight and Obese based on the values. Below is the loop for the same

![enter image description here](https://i.stack.imgur.com/8eoS4.png)

However I am getting an error. I am a beginner. Just started coding 2 weeks back.