How to customise PDB loading for modified PDB files?

[l-Dr-MR-l]

I've got some edited PDB files that contain additional Amino Acid types (HSP for example which is a protonated HIS) which hold some extra information.
I was wondering if there's some easy way to add to the list of recognised AA's so that I can load these with graphein?

[a-r-j]

Hi @l-Dr-MR-l, I'm a little occupied at the moment but you could contribute to this PR: #370

You can find a reference to the list of recognised AAs here: #387 (comment)

[l-Dr-MR-l]

Thanks for the suggestion @a-r-j, I must admit I'm not so experienced with github.
I've pulled the PR and made a change adding HSP. How do I contribute this to the existing PR?