code: def test_cython():
      import dgl._ffi._cy3.core
  
file_path: dgl/tests/python/common/test_ffi.py
imports: import os
  import unittest
  import backend
  import dgl
  import numpy
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_cython() without return types