new to Python - struggling with functions. - Image of code attached.

It inputs the name & scores just fine with the validation checks.
I need to use the scores input by the user and total them. 
However, when I've tried to sum(score) it doesn't like it.
I can't work out how to sum the 4 total scores. 

Please help :) Also would love any feedback on the style of coding etc.
Thanks in advance x

[Image: Code in Python](https://i.stack.imgur.com/R38My.png)