When trying to fit a periodic ParametricSpline() the function does not accept an s argument

Slightly modified example form the runtest.jl:
x = [23. 24. 25. 25. 24. 23.;
13. 12. 12. 13. 13. 13.]
spl = ParametricSpline(x, periodic=true,s=1)

Error message:
ERROR: KeyError: key 1 not found
Stacktrace:
[1] getindex at ./dict.jl:478 [inlined]
[2] _ParametricSpline(::Nothing, ::Array{Float64,2}, ::Nothing, ::Array{Float64,1}, ::Int64, ::Int64, ::String, ::Bool) at /home/user/.julia/packages/Dierckx/9SY4A/src/Dierckx.jl:573
[3] #ParametricSpline#5 at /home/user/.julia/packages/Dierckx/9SY4A/src/Dierckx.jl:433 [inlined]
[4] (::getfield(Core, Symbol("#kw#Type")))(::NamedTuple{(:periodic, :s),Tuple{Bool,Int64}}, ::Type{ParametricSpline}, ::Array{Float64,2}) at ./none:0
[5] top-level scope at none:0

Without s=1 or with s=0 everything works fine

Thanks for your help
Alex