There is something odd about lists of symbols:

```
julia> for i in (1,2); println(i); end
1
2
julia> for i in (1); println(i); end
1
julia> for i in (:ab,:cd); println(i); end
ab
cd
julia> for i in (:ab); println(i); end
ERROR: MethodError: no method matching start(::Symbol)
Closest candidates are:
start(::Core.SimpleVector) at essentials.jl:533
start(::Base.MethodList) at reflection.jl:690
start(::ExponentialBackOff) at error.jl:170
...
Stacktrace:
[1] top-level scope at ./<missing>:?
```

the problem is that (:ab) is not (:ab,), and somehow this interferes with the `in`

interpretation, but other types do not seem to have this problem.

/iaw