This query:
select ('2018-07-07 00:00 + 00'::timestamptz) AT TIME ZONE 'Africa/Sao_Tome'
Returns this result:
2018-07-07 00:00:00.000000
However, according to more than one source, including this one:
https://www.zeitverschiebung.net/en/timezone/africa--sao_tome, it should
have +1 hour offset.
Thanks,
Phil