code: def test_list_add(env):
      t = env.from_string("{{ a + b }}")
      result = t.render(a=["a", "b"], b=["c", "d"])
      assert isinstance(result, list)
      assert result == ["a", "b", "c", "d"]
  
imports: import pytest
  from jinja2._compat import text_type
  from jinja2.exceptions import UndefinedError
  from jinja2.nativetypes import NativeEnvironment
  from jinja2.nativetypes import NativeTemplate
  from jinja2.runtime import Undefined
label_desc: Use image node_id 6 for calling a global function with example usage: test_list_add(env) without return types