code: def test_make_var_names():
      # Check that _make_var_names return the current name when exog is
      # a pandas Series
      exog = pd.Series([1, 2, 3], name="abc")
      assert _make_var_names(exog) == exog.name
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_make_var_names() without return types