HI,
I tried insert into availability values ('product x', '[2018-02-02,2018-03-01]'::daterange); and I got the same result such as insert into availability values ('product x', daterange('2018-02-02', '2018-03-01', '[]').
I tried insert into availability values ('product x', '[2018-02-02,2018-03-01]'::