CREATE USER产生“注意：空字符串无效...”

Question

我正在跟踪https://www.postgresql.org/docs/11/sql-createuser.html上的PostgreSQL文档来创建用户。 psql讨厌我。

# CREATE USER blah WITH ENCRYPTED PASSWORD 'md56f1ed002ab5595859014ebf0951522d9';
NOTICE:  empty string is not a valid password, clearing password
CREATE ROLE

我生成了MD5，就像...

$ md5 -s 'blah'
MD5 ("blah") = 6f1ed002ab5595859014ebf0951522d9

我如何让NOTICE: empty string is not a valid password, clearing password消失并让postgres尊重我希望提供加密密码的愿望？