What I love about Erlang: no "if" statements

no_if.erl

%% @doc Register a new identity.
-spec register_identity(identifier()) -> succeeded().
%% @end
register_identity(Id) -> 
  F = fun () ->
      Identity = get_identity(Id),
      {_, true} = {already_registered, Identity =/= not_found},
      identity_registered(Id)
  end,
  transact(F).

%% @doc Enable an identity.
-spec enable_identity(identifier()) -> succeeded().
%% @end
enable_identity(Id) -> 
  F = fun () ->
      Identity = get_identity(Id),
      {_, true} = {unknown_identity, Identity == not_found},
      {_, true} = {already_enabled, Identity#identities.enabled == true} ,
      identity_enabled(Identity)
  end,
  transact(F).

%% @doc Disable an identity.
-spec disable_identity(identifier()) -> succeeded().
%% @end
disable_identity(Id) -> 
  F = fun() ->
      Identity = get_identity(Id),
      {_, true} = {unknown_identity, Identity == not_found},
      {_, true} = {already_disabled, Identity#identities.enabled == false} ,
      identity_disabled(Identity)
  end,
  transact(F).