pub fn app(
  config: a,
  controller: String,
) -> promise.Promise(Result(domain.Application, String))

pub fn exec_async(
  app: domain.Application,
  method: String,
  req: a,
) -> promise.Promise(Result(b, String))

pub fn exec_sync(
  app: domain.Application,
  method: String,
  req: a,
) -> Result(option.Option(b), String)

pub fn get_key(obj: a, key: String) -> option.Option(b)

pub fn get_parent_key(
  obj: a,
  parent: String,
  key: String,
) -> option.Option(b)

pub fn new_key() -> a

pub fn not_empty(obj: a) -> Bool

pub fn set_key(obj: a, key: String, value: b) -> a

pub fn set_parent_key(
  obj: a,
  parent: String,
  key: String,
  value: b,
) -> a