class_docstr: Unit tests for the
  :func:`~networkx.algorithms.matching.is_perfect_matching` function.
code: def test_dict(self):
      G = nx.path_graph(4)
      assert nx.is_perfect_matching(G, {0: 1, 1: 0, 2: 3, 3: 2})
  
imports: import math
  from itertools import permutations
  from pytest import raises
  import networkx
  from networkx.algorithms.matching import matching_dict_to_set
  from networkx.utils import edges_equal
label_desc: Use image node_id 1 for calling the TestIsPerfectMatching obj's underlying member method code with example usage: obj.test_dict() without return types