code: def test_k_core_Graph_nx(graph_file):
      dataset_path = graph_file.get_path()
      NM = utils.read_csv_for_nx(dataset_path)
      Gnx = nx.from_pandas_edgelist(
          NM, source="0", target="1", create_using=nx.Graph()
      )
      nc = nx.k_core(Gnx)
      cc = cugraph.k_core(Gnx)
  
      assert nx.is_isomorphic(nc, cc)
  
file_path: cugraph/python/cugraph/cugraph/tests/core/test_k_core.py
imports: import gc
  import pytest
  import networkx
  import cugraph
  from cugraph.testing import utils, UNDIRECTED_DATASETS
label_desc: Use image node_id 5 for calling a global function with example usage: test_k_core_Graph_nx(graph_file) without return types