diff --git a/src/ComputationalModels/Drivers.jl b/src/ComputationalModels/Drivers.jl
index cdff982..667901f 100644
--- a/src/ComputationalModels/Drivers.jl
+++ b/src/ComputationalModels/Drivers.jl
@@ -22,11 +22,10 @@ struct StaggeredModel{A,B,C,D} <: ComputationalModel
     state⁻::C
     caches::D
 
-    function StaggeredModel(CompModels::Tuple{Vararg{<:ComputationalModel}},
-        state⁺::Tuple{Vararg{<:FEFunction}},
-        state⁻::Tuple{Vararg{<:FEFunction}})
-
-        @assert(length(CompModels) == length(state⁺) == length(state⁻))
+    function StaggeredModel(
+        CompModels::Tuple{Vararg{ComputationalModel,N}},
+        state⁺::Tuple{Vararg{FEFunction,N}},
+        state⁻::Tuple{Vararg{FEFunction,N}}) where N
 
         x⁺ = map((x) -> get_free_dof_values(x), state⁺)
         x⁻ = map((x) -> get_free_dof_values(x), state⁻)