Receptor rearrangement definition
Each receptor rearrangement is joint by concatenating the concat_cols
sequence fragments https://gitlab.com/b-cell-immunology/scireptor_airr_exporter/-/commit/6bb53b5f31dca75345ede3bbe2096a91d693c70b#note_400840065. Some fwr4_aa
are empty in athero_g07_09 (need to check others). Should these be ignored when creating new receptor_id
s or can a receptor be stored incomplete without this fragment?