code: def test_custom_jinja_env():
      class CustomEnvironment(flask.templating.Environment):
          pass
  
      class CustomFlask(flask.Flask):
          jinja_environment = CustomEnvironment
  
      app = CustomFlask(__name__)
      assert isinstance(app.jinja_env, CustomEnvironment)
  
imports: import logging
  import pytest
  import werkzeug.serving
  from jinja2 import TemplateNotFound
  from markupsafe import Markup
  import flask
label_desc: Use image node_id 32 for calling a global function with example usage: test_custom_jinja_env() without return types