using lgamma evaluated at complex values

[bdeonovic]

My function evaluates the lgamma function at complex values. I ran into the following error:

ERROR: MethodError: no method matching lgamma(::Complex{ForwardDiff.Dual{ForwardDiff.Tag{ElementarySymmetricFunctions.#logLC#42{Array{Float64,1},Array{Int64,1}},Float64},Float64,10}})

MWE:

julia> lgamma(Complex(ForwardDiff.Dual(5.0)))
ERROR: MethodError: no method matching lgamma(::Complex{ForwardDiff.Dual{Void,Float64,0}})
Closest candidates are:
  lgamma(::Float64) at math.jl:419
  lgamma(::Float32) at math.jl:420
  lgamma(::Float16) at math.jl:950
  ...