code: func sameLanguage(a1, a2 *Automaton) bool {
  	if a1 == a2 {
  		return true
  	}
  	return subsetOf(a2, a1) && subsetOf(a1, a2)
  }
docs: /*
  Returns true if these two automata accept exactly the same language.
  This is a costly computation! Note also that a1 and a2 will be
  determinized as a side effect.
  */