update code formatting

gradio_article.md

@@ -13,20 +13,20 @@ Jeremy presented in session 1 of the 2022 fastai course into a regression task.
 
 1. Creating a labeling function that returns a float, 0.0 if it is a DC character and 1.0 if it is a Marvel character
 
-```
+```python
 def is_marvel(img):
     return 1. if img.parent.name.lower().startswith("marvel") else 0.
 ```
 
 2. Updating our `DataBlock`to use a `RegressionBlock` for our targets, and then assigning our labeling function above to the `get_y` argument.
 
-```
+```python
 blocks=(ImageBlock, RegressionBlock)
 ```
 
 3. Updating our call to `vision_learner` to use a regression friendly metric like RMSE, as well as specifying a `y_range` to constrain our predictions to the expected range of between 0 and 1.
 
-```
+```python
 learn = vision_learner(dls, resnet18, metrics=rmse, y_range=(0, 1))
 ```