!7

p {
  assertEqualsVerbose(lithashset("A"), charactersAppearingExactlyOnceInEachString(ll("bggkA"));
  assertEqualsVerbose(lithashset("A"), charactersAppearingExactlyOnceInEachString(ll("bggkA", "Abbl"));
  assertEqualsVerbose(lithashset("A", "B"), charactersAppearingExactlyOnceInEachString(ll("bggkAB", "BAbbl")));
}