code: def identity(x):
      return x
  
file_path: ray/python/ray/workflow/tests/test_serialization.py
imports: import pytest
  import ray
  from ray import workflow
  from ray.tests.conftest import *
  from ray.workflow import serialization
label_desc: Use image node_id 1 for calling a global function with example usage: identity(x) and returns: x