code: def test_setdefault(self):
      d = LRUCache(3)
      assert len(d) == 0
      assert d.setdefault("a") is None
      assert d.setdefault("a", 1) is None
      assert len(d) == 1
      assert d.setdefault("b", 2) == 2
      assert len(d) == 2
  
imports: import pickle
  import random
  from collections import deque
  from copy import copy
  import pytest
  from markupsafe import Markup
  from jinja2._compat import range_type
  from jinja2._compat import string_types
  from jinja2.utils import consume
  from jinja2.utils import generate_lorem_ipsum
  from jinja2.utils import LRUCache
  from jinja2.utils import missing
  from jinja2.utils import object_type_repr
  from jinja2.utils import select_autoescape
  from jinja2.utils import urlize
label_desc: Use image node_id 10 for calling the TestLRUCache obj's underlying member method code with example usage: obj.test_setdefault() without return types