code: def test_siftdown_leaf(self):
      h = [2]
      h_sifted = [2]
      q = self._make_mapped_queue(h)
      q._siftdown(0, 0)
      assert q.heap == h_sifted
      self._check_map(q)
  
imports: import pytest
  from networkx.utils.mapped_queue import MappedQueue, _HeapElement
label_desc: Use image node_id 13 for calling the TestMappedQueue obj's underlying member method code with example usage: obj.test_siftdown_leaf() without return types