code: def test_loop_idx0():
      t = Template(TEST_IDX0_TEMPLATE_STR_1)
      lst = [10]
      excepted_render = "[(len=1, revindex0=0, index0=0, val=10)]"
      assert excepted_render == t.render(lst=lst)
  
file_path: catboost/contrib/python/Jinja2/py3/tests/test_runtime.py
imports: import itertools
  from jinja2 import Template
  from jinja2.runtime import LoopContext
label_desc: Use image node_id 2 for calling a global function with example usage: test_loop_idx0() without return types