code: def test_simple(self):
      @st.cache
      def foo():
          return 42
  
      self.assertEqual(foo(), 42)
      self.assertEqual(foo(), 42)
  
imports: import threading
  import types
  from unittest.mock import Mock, patch
  from parameterized import parameterized
  import streamlit
  from streamlit.elements import exception
  from streamlit.proto.Exception_pb2 import Exception
  from streamlit.runtime.legacy_caching import caching, hashing
  from tests import testutil
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 2 for calling the CacheTest obj's underlying member method code with example usage: obj.test_simple() and returns: int