code: def graph_data_loader(request, data_source):
      """Returns a GraphDataLoader instance."""
      data_loader = GraphDataLoader(data_source, backend=request.param)
      yield data_loader
      data_loader.clean()
  
file_path: AmpliGraph/tests/ampligraph/datasets/test_graph_data_loader.py
imports: from ampligraph.datasets import GraphDataLoader, NoBackend
  from ampligraph.datasets.sqlite_adapter import SQLiteAdapter
  import pytest
  import numpy
  import pandas
label_desc: Use image node_id 2 for calling a global function with example usage: graph_data_loader(request, data_source) without return types