Resetting the lock_timeout value for a transaction

Hi folks,

I have been using:

-- Setting the SESSION lock timeout to 10 seconds
SET lock_timeout = '10s';

-- Setting the TRANSACTION lock timeout to 20 seconds
BEGIN;
SET LOCAL lock_timeout = '20s';
COMMIT;

However, I have been caught by the behaviour of "RESET lock_timeout;" when
inside and outside a transaction.

-- Resets the lock_timeout value for the SESSION.
RESET lock_timeout;

-- WARNING: This will reset BOTH the SESSION and TRANSACTION lock_timeouts.
BEGIN;
SET LOCAL lock_timeout = '20s';
RESET lock_timeout;
COMMIT;

I would have expected that the "RESET lock_timeout;" inside a transaction would
only reset the value of lock_timeout for that specific transaction. Or else,
there would be an equivalent "RESET LOCAL lock_timeout;" to be used for that.

But I can't find anything that does just that.
Am I missing something? Example script for convenience:

-- This is the default lock_timeout (0s)
SHOW lock_timeout;

-- Set the SESSION lock timeout (42s)
SET lock_timeout = '42s';
SHOW lock_timeout;

BEGIN;

-- WARNING: This will set a new value for the SESSION lock_timeout from within
-- the transaction because it is missing the LOCAL key word!
SET lock_timeout = '10s';
SHOW lock_timeout;

-- Set it again but this time only for the transaction. This value will not
-- affect the session lock_timeout.
SET LOCAL lock_timeout = '9s';
SHOW lock_timeout;

-- Reset BOTH the SESSION and Transaction lock_timeout (both go back to 0, the
-- default).
RESET lock_timeout;
SHOW lock_timeout;

COMMIT;

-- Should now be 0s because it was reset inside the transaction.
SHOW lock_timeout;

Thanks, Marcelo