Bugfix

The model receives the prompt (and optional system message). The run uses scorer contains_all with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Fix the bug and return corrected Python code only.

def last_item_05(items):
    if len(items) == 0:
        return items[-1]
    return None

{
  "expected_contains": [
    "if len(items) == 0",
    "return None",
    "items[-1]"
  ]
}