Fix SWIFT transactions: error unmarshaling MT940

[Clauscomputing]

Hi,
this fixes

error unmarshaling SWIFT transactions: error unmarshaling MT940: *swift.TransactionTag: Malformed marshaled value

for something like
:61:221214C115,83NMSCNONREF.

According to Gesamtdok_HBCI22.pdf page 753 these values are not mandatory and len(runes) can be 0.

[mitch000001]

Can you point out with which bank institute the issue happened? It seems every institute is providing its own flavor of swift implementation.

[Clauscomputing]

What do you mean by flavor? Is page 753 not the right spec?

[mitch000001]

I guess it is, it just happened to me that some institutes like Sparkasse had a different implementation than implemented here. Therefore I just wanted to document somehow which institute would work for sure with that fix.

[Clauscomputing]

Does this fix interfere with with your Sparkasse?

[mitch000001]

I tried the code, works just fine.

[Clauscomputing]

Thanks