What does the + and - after a line numbering mean?

I keep getting the error message Row 2 should contain values [3 ‘San Francisco’ 90], but instead contains [3 ‘San Fancisco’ 90].

My code is exactly the same, the only difference is the + and - on line 7 & 10. What does the +/- mean and how do I change it?

Screenshot 2022-08-18 at 08.45.06|690x440

The +/- is showing you the lines where the code is different. There’s also a highlight where the code is different.
So, on line 10 there’s a couple of extra spaces around the equals sign - which isn’t much of an issue.
And on line 7, there’s a character highlighted on the right which is missing on the left.

Hope that helps