code: def test_backend():
      environ = os.environ.get("AUTOGL_BACKEND", None)
      backend_name = autogl.backend.DependentBackend.get_backend_name()
      if environ in ["pyg", "dgl"]:
          assert backend_name == environ
      else:
          try:
              import dgl
  
              assert backend_name == "dgl"
              return
          except ImportError:
              pass
  
          try:
              import torch_geometric
  
              assert backend_name == "pyg"
              return
          except ImportError:
              pass
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_backend() without return types