There is no underscore in Ensembl IDs, so this would always evaluate to false for Ensembl Protein IDs: https://github.com/VariantEffect/dcd_mapping2/blob/138dad4d4c50eea49c09d89aabeee59a4b96389c/src/dcd_mapping/transcripts.py#L441
There is no underscore in Ensembl IDs, so this would always evaluate to false for Ensembl Protein IDs:
dcd_mapping2/src/dcd_mapping/transcripts.py
Line 441 in 138dad4