Well since you don't ask me for a definition, maybe you will answer some questions for me. How is the evolution of a lung with respect to a swim bladder taught in school? How is the evolution of a tetrapod with respect to a lobe-finned fish taught in the same class?
I don't know how those items are taught. I haven't reviewed any school textbooks to check. I don't know even if they are taught in the same class.
However, Google can be your friend: Link Link Link.pdf Link
Most of the articles point out that it's not known whether the lung evolved from the swim bladder or vice verse but the current opinion favors the latter.