🎯 Todo

For the parsers in io.hitran, only groups 1-2 and classes 1, 4-6 are implemented.
Notably, group 6 and class 3 are missing which are needed for linear diatomic molecules.
But this is surprising to me as I never had issues with this... am I missing something?

How they should be parsed can be found in the HITRAN2004 paper:
https://hitran.org/media/refs/HITRAN-2004.pdf
tables 3 & 4.