code: def test_let():
      assert settings.foo == "bar"
  
      with let(settings, foo="hello"):
          assert settings.foo == "hello"
  
      assert settings.foo == "bar"
  
      with settings._let(foo="hello"):
          assert settings.foo == "hello"
  
      assert settings.foo == "bar"
  
file_path: gluonts/test/core/test_settings.py
imports: from gluonts.core.settings import Settings, let
  from gluonts.pydantic import BaseModel
label_desc: Use image node_id 4 for calling a global function with example usage: test_let() without return types