code: def _check_map(self, q):
      assert q.position == {elt: pos for pos, elt in enumerate(q.heap)}
  
imports: import pytest
  from networkx.utils.mapped_queue import MappedQueue, _HeapElement
label_desc: Use image node_id 2 for calling the TestMappedQueue obj's underlying member method code with example usage: obj._check_map(q) without return types