fix example

README.md

@@ -87,8 +87,8 @@ os.environ["HF_ALLOW_CODE_EVAL"] = "1"
 # Login using e.g. `huggingface-cli login` to access this dataset
 ds = load_dataset("PNYX/ds1000_pnyx", "Numpy")
 
-solution_code = ds['easy'][0]['solution_function']
-test_code = ds['easy'][0]['test_code']
+solution_code = ds['test'][0]['solution_function']
+test_code = ds['test'][0]['test_code']
 
 # run simple test 
 pass_at_k = hf_evaluate.load("code_eval")