def _run_wsgi_app(*args):
 global _run_wsgi_app
 from werkzeug.test import run_wsgi_app as _run_wsgi_app
 return _run_wsgi_app(*args)

def _run_wsgi_app ( * args ) : global _run_wsgi_app from werkzeug . test import run_wsgi_app as _run_wsgi_app return _run_wsgi_app ( * args )
this function replaces itself to ensure that the test module is not imported unless required .