Fix error from 4830.

ci/notebook_list.py

@@ -31,6 +31,16 @@ def skip_book_dir(runtype):
     return runtype in runtype_dict and Path(runtype_dict.get(runtype)).is_file()
 
 
+def _get_cuda_version_string():
+    status, version = runtime.getLocalRuntimeVersion()
+    if status != runtime.cudaError_t.cudaSuccess:
+        raise RuntimeError("Could not get CUDA runtime version.")
+    major, minor = divmod(version, 1000)
+    minor //= 10
+    return f"{major}.{minor}"
+
+cuda_version_string = _get_cuda_version_string()
+
 parser = argparse.ArgumentParser(description="Condition for running the notebook tests")
 parser.add_argument("runtype", type=str)