Oops, needed the codomain modified after all

src/categorical_algebra/FinCats.jl

@@ -567,7 +567,7 @@ allow for types such as that of identity morphisms upon mutation.
 function dom_to_graph(F::FinDomFunctor{Dom,<:Cat{Ob,Hom}},obtype=Ob,homtype=Hom) where {Dom,Ob,Hom} 
   D = dom(F)
   C = FinCat(graph(D))
-  FinDomFunctorMap(obtype[ob_map(F,ob) for ob in ob_generators(D)],homtype[hom_map(F,hom) for hom in hom_generators(D)],C,codom(F))
+  FinDomFunctorMap(obtype[ob_map(F,ob) for ob in ob_generators(D)],homtype[hom_map(F,hom) for hom in hom_generators(D)],C,TypeCat(obtype,homtype))
 end
 function Base.show(io::IO, F::T) where T <: FinDomFunctorMap
   Categories.show_type_constructor(io, T); print(io, "(")