--- a/src/SbpOperators/boundaryops/normal_derivative.jl	Tue May 02 20:14:39 2023 +0200
+++ b/src/SbpOperators/boundaryops/normal_derivative.jl	Tue May 02 22:09:33 2023 +0200
@@ -1,16 +1,21 @@
 """
-    normal_derivative(g, closure_stencil::Stencil, boundary)
+    normal_derivative(g, stencil_set::StencilSet, boundary)
+    normal_derivative(g::TensorGrid, stencil_set::StencilSet, boundary::TensorGridBoundary)
+    normal_derivative(g::EquidistantGrid, stencil_set::StencilSet, boundary)
 
 Creates the normal derivative boundary operator `d` as a `LazyTensor`
 
-`d` computes the normal derivative of a grid function  on `boundary` a `Stencil` `closure_stencil`.
-`d'` is the prolongation of the normal derivative of a grid function to the whole grid using the same `closure_stencil`.
-On a one-dimensional `grid`, `d` is a `BoundaryOperator`. On a multi-dimensional `grid`, `d` is the inflation of
-a `BoundaryOperator`.
+`d` computes the normal derivative of a grid function  on `boundary` using the
+'d1' stencil in the given stencil_set. `d'` is the prolongation of the normal
+derivative of a grid function to the whole grid using the same stencil. On a
+one-dimensional `grid`, `d` is a `BoundaryOperator`. On a multi-dimensional
+`grid`, `d` is the inflation of a `BoundaryOperator`.
 
 See also: [`BoundaryOperator`](@ref), [`LazyTensors.inflate`](@ref).
 """
-#TODO: Check docstring
+function normal_derivative end
+
+
 function normal_derivative(g::TensorGrid, stencil_set::StencilSet, boundary::TensorGridBoundary)
     op = normal_derivative(g.grids[grid_id(boundary)], stencil_set, boundary_id(boundary))
     return LazyTensors.inflate(op, size(g), grid_id(boundary))