Protein.count_chains: def of bend-prot@0.1.0.0
Import: import bend-prot@0.1.0.0/protein.bend as Protein
Lines 149-154 of bend-prot@0.1.0.0/protein.bend: https://jend.leeeet.dev/read.txt?path=bend-prot@0.1.0.0/protein.bend&start_line=149&end_line=154

import Base

def count_chains(xs: List<&2, Chain>) -> Nat:
  match xs:
    case Nil{}:
      0n
    case h <> t:
      1n+count_chains(t)

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=bend-prot@0.1.0.0/protein.bend&name=Chain