create_node(zk, path) :: :ok | {:error, term}

create_nodes(zk, [path]) :: :ok | {:error, term}

get_children(zk, path, watcher | nil) ::
  {:ok, [child_node :: String.t]} |
  {:error, term}

get_children_with_data(zk, path, watcher | nil) ::
  {:ok, [{child_node :: String.t, data :: binary}]} |
  {:error, term}

get_data(zk, path, watcher | nil) ::
  {:ok, term} |
  {:error, term}