def write_chain
import bend-prot@0.1.0.0/pdb.bend as Pdbimport Base
import bend-prot@0.1.0.0/protein.bend as P
600def write_chain(c: P.Chain) -> List<&2, String>:
601 match c:
602 case P.Chain{cid, residues}:
603 write_residues(residues, SCon{Char.from_u32(cid), SNil{}})