missing convert?

[bc0n]

  pa = Point(3u"m", 4u"m")
  pb = Point(5u"m", 4.8u"m")
  vab = Vector2D(pa, pb)  
  @show aAB = Geometry2D.angle(vab)

ERROR: MethodError: no method matching (Union{Unitful.Quantity{T, NoDims, Unitful.FreeUnits{(rad,), NoDims, nothing}}, Unitful.Quantity{T, NoDims, Unitful.FreeUnits{(°,), NoDims, nothing}}} where T)(::Float64)
Closest candidates are:
(::Type{T})(::T) where T<:Number at boot.jl:772
(::Type{T})(::AbstractChar) where T<:Union{AbstractChar, Number} at char.jl:50
(::Type{T})(::Base.TwicePrecision) where T<:Number at twiceprecision.jl:266
...
Stacktrace:
[1] convert(#unused#::Type{Union{Unitful.Quantity{T, NoDims, Unitful.FreeUnits{(rad,), NoDims, nothing}}, Unitful.Quantity{T, NoDims, Unitful.FreeUnits{(°,), NoDims, nothing}}} where T}, x::Float64)
@ Base .\number.jl:7
[2] angle(v::Geometry2D.Vector2D)
@ Geometry2D \src\Vector2D.jl:49