update readme

README.md

@@ -20,7 +20,7 @@ The **Proof-Pile-2** is a 55 billion token dataset of mathematical and scientifi
 - `algebraic-stack` (11B tokens): A new dataset of mathematical code, including numerical computing, computer algebra, and formal mathematics.
 
 You can download the dataset as follows
-```
+```python
 from datasets import load_dataset
 ds = load_dataset("EleuetherAI/proof-pile-2")
 
@@ -30,7 +30,7 @@ ds_arxiv = load_dataset("EleutherAI/proof-pile-2", "arxiv")
 
 ### Schema
 Each dataset row has the following structure
-```
+```python
 {
   "text": ..., # document text
   "meta": ..., # JSON string of metadata, schema specific to data source