code: def load_proteins(dataset):
      """
      This function downloads, converts, and load Proteins graph dataset
      Parameter
      ---------
      dataset: output folder name
      """
      part_dir = dataset
      graph_file = os.path.join(part_dir + "/graph.dgl")
  
      if not os.path.exists("proteins.mtx"):
          download_proteins()
      if not os.path.exists(graph_file):
          g = proteins_mtx2dgl()
          save(g, dataset)
      ## load
      graph = load_graphs(graph_file)[0][0]
      return graph
  
file_path: dgl/python/dgl/distgnn/tools/tools.py
imports: import os
  import random
  import requests
  import torch
  from scipy.io import mmread
  import dgl
  from dgl.base import DGLError
  from dgl.data.utils import load_graphs, save_graphs, save_tensors
label_desc: Use image node_id 5 for calling a global function with example usage: load_proteins(dataset) and returns: graph