writer.py: rebase with FreeCAD#8362

src/Mod/Fem/femsolver/elmer/writer.py

@@ -735,7 +735,7 @@ def _handleElasticityBodyForces(self, bodies):
         if obj is not None:
             for name in bodies:
                 gravity = self.convert(self.constsdef["Gravity"], "L/T^2")
-                if self.getBodyMaterial(name) == None:
+                if self.getBodyMaterial(name) is None:
                     raise WriteError(
                         "The body {} is not referenced in any material.\n\n".format(name)
                     )
@@ -1721,7 +1721,7 @@ def _haveMaterialSolid(self):
         for obj in self.getMember("App::MaterialObject"):
             m = obj.Material
             # fluid material always has KinematicViscosity defined
-            if not ("KinematicViscosity" in m):
+            if not "KinematicViscosity" in m:
                 return True
         return False
 
@@ -1776,9 +1776,9 @@ def _getMeshDimension(self):
         obj = self._getSingleMember("Fem::FemMeshObject")
         if obj.Part.Shape.Solids:
             return 3
-        elif obj.Part.Shape.Faces:
+        if obj.Part.Shape.Faces:
             return 2
-        elif obj.Part.Shape.Edges:
+        if obj.Part.Shape.Edges:
             return 1
         return None