I'm trying to combine two variables `@a` and `@b` into a string, with the variables values separated by a comma. This is my attempt:

```
p {
    @a: inset 0 1px 1px rgba(0, 0, 0, 0.075);
    @b: 0 0 8px rgba(82, 168, 236, 0.6);
    box-shadow: ~"@{a}, @{b}";
}

```

Output:

```
p {box-shadow: [object Object],[object Object]}

```

Expected:

```
p {box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6)}

```

What am I doing wrong?