default behavior for flatten/unflatten with any type

Hi,
I'm using ParameterHandling only for the flatten/unflatten tools. In my case I need to carry extra information within my tuple stored in different type that do not need to be flatten but I need to recover it in my restructured NamedTuple
Here is an example

struct MyType
       a::Float64
       b::Int
end

mynametuple = (;a=rand(2),b=randn(6),m = MyType(1,2))

If I try to flatten this tuple I get an error:

flatvector, restructure = ParameterHandling.flatten( mynametuple)
ERROR: MethodError: no method matching flatten(::Type{Float64}, ::MyType)

Closest candidates are:
  flatten(::Type{T}, ::Tuple{}) where T<:Real
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:92
  flatten(::Type{T}, ::Nothing) where T<:Real
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:22
  flatten(::Type{T}, ::Integer) where T<:Real
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:28
  ...

Stacktrace:
 [1] flatten(::Type{Float64}, x::Tuple{MyType})
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:82
 [2] flatten(::Type{Float64}, x::Tuple{Vector{Float64}, MyType})
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:83
 [3] flatten(::Type{Float64}, x::Tuple{Vector{Float64}, Vector{Float64}, MyType})
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:83
 [4] flatten(::Type{Float64}, x::@NamedTuple{a::Vector{Float64}, b::Vector{Float64}, m::MyType})
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:99
 [5] flatten(x::@NamedTuple{a::Vector{Float64}, b::Vector{Float64}, m::MyType})
   @ ParameterHandling ~/.julia/packages/ParameterHandling/WkHof/src/flatten.jl:20
 [6] top-level scope
   @ REPL[14]:1

However, with this simple overloading of ParameterHandling.flatten as a default behaviour

function ParameterHandling.flatten(::Type{T}, x) where {T<:Real}
           v = T[]
           unflatten_to_Any(::Vector{T}) = x
           return v, unflatten_to_Any
 end

I get:

julia> flatvector, restructure = ParameterHandling.flatten( mynametuple)
([0.8409925019315632, 0.2819056254106582, 1.598581283953101, 0.3921407396316173, -1.6414335944803775, 1.0503960727007877, -1.183085803897985, -2.3827810941365573], ParameterHandling.var"#unflatten_to_NamedTuple#15"{Float64, @NamedTuple{a::Vector{Float64}, b::Vector{Float64}, m::MyType}, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_empty_Tuple#14"{Float64, Tuple{}}, var"#unflatten_to_Any#6"{Float64, MyType}}, ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}}, ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}}}((a = [0.8409925019315632, 0.2819056254106582], b = [1.598581283953101, 0.3921407396316173, -1.6414335944803775, 1.0503960727007877, -1.183085803897985, -2.3827810941365573], m = MyType(1.0, 2)), ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_empty_Tuple#14"{Float64, Tuple{}}, var"#unflatten_to_Any#6"{Float64, MyType}}, ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}}, ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}}(6, 2, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_empty_Tuple#14"{Float64, Tuple{}}, var"#unflatten_to_Any#6"{Float64, MyType}}, ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}}(0, 6, ParameterHandling.var"#unflatten_to_Tuple#13"{Float64, Int64, Int64, ParameterHandling.var"#unflatten_to_empty_Tuple#14"{Float64, Tuple{}}, var"#unflatten_to_Any#6"{Float64, MyType}}(0, 0, ParameterHandling.var"#unflatten_to_empty_Tuple#14"{Float64, Tuple{}}(()), var"#unflatten_to_Any#6"{Float64, MyType}(MyType(1.0, 2))), ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}()), ParameterHandling.var"#unflatten_to_Vector#4"{Float64, Float64}())))

julia> restructure(flatvector)
(a = [0.8409925019315632, 0.2819056254106582], b = [1.598581283953101, 0.3921407396316173, -1.6414335944803775, 1.0503960727007877, -1.183085803897985, -2.3827810941365573], m = MyType(1.0, 2))

Is there any reason for not implementing such default behavior? Am I missing something?
Should I make a PR?

Start with src/flatten.jl, especially the methods around the reported stack-trace locations, and reproduce the NamedTuple example with a custom MyType. Check how flatten and the returned restructure function handle unsupported values. Done means a default behavior for such values is defined and the example can flatten and reconstruct the original MyType without errors.