Function finish_assembly 

fn finish_assembly<'a>(
    started: StartedAssembly,
    config: &JigsawConfig,
    rng: &mut LegacyRandom,
    pools: &'a FxHashMap<Identifier, TemplatePoolData>,
    templates: &'a FxHashMap<Identifier, TemplateData>,
    alias_map: &FxHashMap<Identifier, Identifier>,
    get_height: &mut dyn FnMut(i32, i32) -> i32,
    min_y: i32,
    max_y: i32,
) -> AssemblyResult