added sanity check to prevent more than one operation at the same time

Author: gonzalocasas

src/compas_fab/ghpython/components/Cf_CollisionMesh/code.py

@@ -12,16 +12,25 @@
 class CollisionMeshComponent(component):
     def RunScript(self, scene, M, name, add, append, remove):
         ok = False
+        self.Message = ""
+
+        if (add and append) or (append and remove) or (add and remove):
+            self.Message = "Use only one operation at a time\n(add, append or remove)"
+            raise Exception(self.Message)
+
         if scene and M and name:
             mesh = RhinoMesh.from_geometry(M).to_compas()
             collision_mesh = CollisionMesh(mesh, name)
             if add:
                 scene.add_collision_mesh(collision_mesh)
+                self.Message = "Added"
                 ok = True
             if append:
                 scene.append_collision_mesh(collision_mesh)
+                self.Message = "Appended"
                 ok = True
             if remove:
                 scene.remove_collision_mesh(name)
+                self.Message = "Removed"
                 ok = True
         return ok