Not type stable

[roflmaostc]

Would be good to fix

julia> @code_warntype gaussian_sep((128, 128))
MethodInstance for SeparableFunctions.gaussian_sep(::Tuple{Int64, Int64})
  from gaussian_sep(sz::Tuple{Vararg{Int64, N}}, args...; kwargs...) where N @ SeparableFunctions ~/.julia/packages/SeparableFunctions/qwiQm/src/specific.jl:71
Static Parameters
  N = 2
Arguments
  #self#::Core.Const(SeparableFunctions.gaussian_sep)
  sz::Tuple{Int64, Int64}
  args::Tuple{}
Body::Any
1 ─ %1 = SeparableFunctions.:(var"#gaussian_sep#38")::Core.Const(SeparableFunctions.var"#gaussian_sep#38")
│   %2 = Core.NamedTuple()::Core.Const(NamedTuple())
│   %3 = Base.pairs(%2)::Core.Const(Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}())
│   %4 = Core.tuple(%3, #self#, sz)::Tuple{Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}, typeof(gaussian_sep), Tuple{Int64, Int64}}
│   %5 = Core._apply_iterate(Base.iterate, %1, %4, args)::Any
└──      return %5

[RainerHeintzmann]

Is typestable now