code: def _get_dgl_url(file_url):
      """Get DGL online url for download."""
      dgl_repo_url = "https://data.dgl.ai/"
      repo_url = os.environ.get("DGL_REPO", dgl_repo_url)
      if repo_url[-1] != "/":
          repo_url = repo_url + "/"
      return repo_url + file_url
  
imports: from __future__ import absolute_import
  import errno
  import hashlib
  import os
  import pickle
  import sys
  import warnings
  import networkx.algorithms
  import numpy
  import requests
  from tqdm import tqdm
  from ..None import backend
  from .graph_serialize import load_graphs, load_labels, save_graphs
  from .tensor_serialize import load_tensors, save_tensors
label_desc: Use image node_id 2 for calling a global function with example usage: _get_dgl_url(file_url) and returns: unknown