code: def test_k_core_Graph(graph_file):
      cu_kcore, nx_kcore = calc_k_cores(graph_file, False)
  
      assert compare_edges(cu_kcore, nx_kcore)
  
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 4 for calling a global function with example usage: test_k_core_Graph(graph_file) without return types