['The', 'validity', 'of', 'semi', '-', 'classical', 'boundary', 'conditions', 'for', 'the', 'WTE', 'as', 'introduced', 'in', '[', '8', ']', 'is', 'a', 'topic', 'under', 'vivid', 'debate', ',', 'especially', 'after', 'recent', 'works', 'which', 'address', 'the', 'non', '-', 'uniqueness', 'and', 'the', 'symmetry', 'properties', 'of', 'the', 'Wigner', 'function', '[', '27,28,46', ']', '.']