Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfile2DLayersHelper.cs
===================================================================
diff -u -r03bb865f66b346c37c91f2cd8a442abbb2952cba -rcf0567f44aa3a03deabb57101f5b67aa69368ff6
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfile2DLayersHelper.cs	(.../MacroStabilityInwardsSoilProfile2DLayersHelper.cs)	(revision 03bb865f66b346c37c91f2cd8a442abbb2952cba)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfile2DLayersHelper.cs	(.../MacroStabilityInwardsSoilProfile2DLayersHelper.cs)	(revision cf0567f44aa3a03deabb57101f5b67aa69368ff6)
@@ -34,7 +34,8 @@
         /// Method for obtaining all <see cref="MacroStabilityInwardsSoilLayer2D"/> in <paramref name="layers"/> recursively.
         /// </summary>
         /// <param name="layers">The collection of layers to recursively get the layers from.</param>
-        /// <returns>An enumerable with <see cref="MacroStabilityInwardsSoilLayer2D"/>, if there are any.</returns>
+        /// <returns>An enumerable with <see cref="MacroStabilityInwardsSoilLayer2D"/> or an empty enumerable
+        /// when <paramref name="layers"/> is <c>null</c>.</returns>
         public static IEnumerable<MacroStabilityInwardsSoilLayer2D> GetLayersRecursively(IEnumerable<MacroStabilityInwardsSoilLayer2D> layers)
         {
             return layers?.SelectMany(GetLayersRecursively) ?? Enumerable.Empty<MacroStabilityInwardsSoilLayer2D>();