diff --git a/src/differentiation/vecjac_products.jl b/src/differentiation/vecjac_products.jl
index c40bcc06..922d30b2 100644
--- a/src/differentiation/vecjac_products.jl
+++ b/src/differentiation/vecjac_products.jl
@@ -1,25 +1,3 @@
-function _numargs(f)
-    typ = Tuple{Any, Val{:analytic}, Vararg}
-    typ2 = Tuple{Any, Type{Val{:analytic}}, Vararg} # This one is required for overloaded types
-    typ3 = Tuple{Any, Val{:jac}, Vararg}
-    typ4 = Tuple{Any, Type{Val{:jac}}, Vararg} # This one is required for overloaded types
-    typ5 = Tuple{Any, Val{:tgrad}, Vararg}
-    typ6 = Tuple{Any, Type{Val{:tgrad}}, Vararg} # This one is required for overloaded types
-    numparam = maximum([(m.sig<:typ || m.sig<:typ2 || m.sig<:typ3 || m.sig<:typ4 || m.sig<:typ5 || m.sig<:typ6) ? 0 : num_types_in_tuple(m.sig) for m in methods(f)])
-    return (numparam-1) #-1 in v0.5 since it adds f as the first parameter
-end
-
-
-#Get the number of parameters of a Tuple type, i.e. the number of fields.
-
-function num_types_in_tuple(sig)
-  length(sig.parameters)
-end
-
-function num_types_in_tuple(sig::UnionAll)
-  length(Base.unwrap_unionall(sig).parameters)
-end
-    
 function num_vecjac!(
     du,
     f,
@@ -29,10 +7,6 @@ function num_vecjac!(
     cache2 = similar(v);
     compute_f0 = true,
 )
-    if _numargs(f) != 2
-        du .= num_jacvec(f, x, v)
-        return du
-    end
     compute_f0 && (f(cache1, x))
     T = eltype(x)
     # Should it be min? max? mean?