Check if there is any gcode in the scene before executing a post process

plugins/PostProcessingPlugin/PostProcessingPlugin.py

@@ -54,6 +54,9 @@ class PostProcessingPlugin(QObject, Extension):
     ##  Execute all post-processing scripts on the gcode.
     def execute(self, output_device):
         scene = Application.getInstance().getController().getScene()
+        # If the scene does not have a gcode, do nothing
+        if not hasattr(scene, "gcode_dict"):
+            return
         gcode_dict = getattr(scene, "gcode_dict")
         if not gcode_dict:
             return