create(map) :: {:ok, map} | {:error, binary}

delete(binary) :: {:ok, map} | {:error, binary}

index() :: {:ok, map} | {:error, binary}

index(map) :: {:ok, map} | {:error, binary}

pay(id :: binary, customer_or_source :: Keyword.t) ::
  {:ok, map} |
  {:error, binary}

show(binary) :: {:ok, map} | {:error, binary}

update(map) :: {:ok, map} | {:error, binary}

update(binary, map) :: {:ok, map} | {:error, binary}