ProofBase.get_append_len: law of minebender-game@1.0.0.0
Import: import minebender-game@1.0.0.0/proof_base.bend as ProofBase
Lines 288-294 of minebender-game@1.0.0.0/proof_base.bend: https://jend.leeeet.dev/read.txt?path=minebender-game@1.0.0.0/proof_base.bend&start_line=288&end_line=294

import Base

law get_append_len:
  for -A: Data
  for +xs: List<&2, A>
  for +v: A
  for +ys: List<&2, A>
  {List.get(&2, A, List.append(&2, A, xs, v <> ys), List.length(&2, A, xs)) == Some{v}
    : Maybe<&2, A>}

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.get
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.length
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe