Hi,

I’m new to Julia and this might be something very simple but I’m struggling to implement in JuMP.

```
julia> using JuMP
julia> using MosekTools
julia> model = Model();
julia> @variable(model, x)
x
julia> a = [x 2x
0 x];
julia> b = [1 2
3 4];
julia> cref = @SDconstraint(model, a ⪰ b)
ERROR: UndefVarError: @SDconstraint not defined
```

What am I doing wrong here? This is borrowed from an example given here