Typo in pHLAIformer.py that leads to unexpected behavior

[lshh125]

Hello dear authors,

Thank you for the great tool.

While I'm trying it out, it repeatedly fail to read my hla fasta files. After some debugging, I found that there is a typo in pHLAIformer.py line 119, where it should be hla_seq.isalpha() instead of hla.isalpha(). Otherwise, it's just checking if the raw input from last line of the input file is alpha, and will quit because it's usually end with '\n'.

Best,
Shaoheng