code: def postprocess_fn(x, thresh: float):
      return (x > thresh)[0]
  
file_path: chitra/tests/serve/test_app.py
imports: import unittest.mock
  from unittest.mock import MagicMock
  import numpy
  import pytest
  from chitra.serve import GradioApp
  from chitra.serve import constants
label_desc: Use image node_id 3 for calling a global function with example usage: postprocess_fn(x, thresh) and returns: unknown