code: def test_validate_var_args():
      groups = {
          "test": {
              "functions": [
                  {
                      "args": [
                          {"name": "bad", "is_var_args": True},
                          {"name": "ok"},
                      ],
                      "since": "1.0",
                      "doc": "doc",
                      "expr_class": "class",
                  }
              ]
          }
      }
      with pytest.raises(AssertionError) as error:
          rt.prepare_definitions(groups)
          assert "var args" in error.value
  
imports: import pytest
  import render_template
label_desc: Use image node_id 2 for calling a global function with example usage: test_validate_var_args() without return types