I'm aware that this question is asked a lot on here but I've been looking through the other questions and I haven't found any which used a .csv file. 

Here is my csv file:

> 
> 
> ```
> Survived, Pclass, Sex, Age, Siblings, Parents, Fare  
> 0, 3, male, 22.0, 1, 0, 7.25  
> 1, 1, female, 38.0, 1, 0, 71.2833  
> 1,3,female, 26.0, 0, 0, 7.925  
> 1, 1, female, 35.0, 1, 0, 53.1
> 
> ```
> 
> 

And my code:

```
import pandas as pd  
df = pd.read_csv("titanic.csv")  
print(df)  
print(df.columns)  
print(df["Pclass"])

```

Lines 3 and 4 of my code work perfectly, so there probably isn't an issue with the second line or with the csv file itself, right? Line 5 is where it goes wrong. This is the error message:
![This is the error message.](https://i.stack.imgur.com/4rpFb.png)

What's strange is that when I try to do line 5 with 'Survived', the first heading in the file, it works. It's only with the other headings that this error occurs.
I'm using Python version 3.7.1 and pandas version 1.0.3 if that helps.