Somewhere in your code you are multiplying a string by a variable from JuMP. The full error message also contains a stacktrace which you can look through the determine which line is the culprit (I’m fairly sure it’s because of what’s in data, but you’ll have to look into that yourself)
When you paste code in discourse, you should do so in “triple bacticks”. I.e.
```
your code
```
comes out looking like:
your code
which makes it much easier to read. It looks like you tried to do that with quotes, but the correct symbol is the “backtick” which (on an american keyboard at least) is to the left of the number keys (the same key as ~).