function fit_routine(model::Function,xdata::Array{<:Real},ydata::Array{uwreal},param::Int64=3;wpm::Union{Dict{Int64,Vector{Float64}},Dict{String,Vector{Float64}},Nothing}=nothing)
function fit_routine(model::Function,xdata::Array{<:Real},ydata::Array{uwreal},param::Int64=3;info::Bool=false,wpm::Union{Dict{Int64,Vector{Float64}},Dict{String,Vector{Float64}},Nothing}=nothing,correlated_fit::Bool=false)