code: def id(x, y, z):
      return x, y, z
  
file_path: nipy/nipy/labs/datasets/transforms/tests/test_transform.py
imports: import copy
  import numpy
  import pytest
  from ..transform import CompositionError, Transform
label_desc: Use image node_id 1 for calling a global function with example usage: id(x, y, z) and returns: x,  y,  z