code: def ensure_local_data(prefix):
      if not os.path.exists(f"{prefix}.zip"):
          print(f"Downloading MovieLens data: {prefix}")
          # MovieLens 100k dataset from https://grouplens.org/datasets/movielens/
          # This dataset is copy right to GroupLens Research Group at the University of Minnesota,
          # and licensed under their usage license.
          # For full text of the usage license, see http://files.grouplens.org/datasets/movielens/ml-100k-README.txt
          os.system(
              f"wget http://files.grouplens.org/datasets/movielens/{prefix}.zip"
          )
          os.system(f"unzip {prefix}.zip")
  
imports: import os
  import mxnet
  from mxnet import gluon
label_desc: Use image node_id 2 for calling a global function with example usage: ensure_local_data(prefix) without return types