An object which is Tuple, but not an NTuple{N, Any}

[Tamas_Papp]

foo(::Type{<:Tuple}) = "I am some generic tuple type"
foo(::Type{<:NTuple{N,Any}}) where N = "I know my length, and it is $N"
foo(Tuple)              # will call first method
foo(Tuple{Int,Float64}) # will call second method