code: def test_init(self):
      d = {5: 0, 4: 1, "a": 2, 2: 3, 1: 4}
      q = MappedQueue(d)
      assert q.position == d
  
imports: import pytest
  from networkx.utils.mapped_queue import MappedQueue, _HeapElement
label_desc: Use image node_id 2 for calling the TestMappedDict obj's underlying member method code with example usage: obj.test_init() without return types