Simple password check does not allow empty passwords even when all options are set to 0

install soname 'simple_password_check';

set global

  simple_password_check_digits = 0,

  simple_password_check_letters_same_case = 0,

  simple_password_check_other_characters = 0;

set global

  simple_password_check_minimal_length = 0;

show variables like 'simple_password%';

set password = password('');

Variable_name	Value

simple_password_check_digits	0

simple_password_check_letters_same_case	0

simple_password_check_minimal_length	0

simple_password_check_other_characters	0

set password = password('');

...

mysqltest: At line 13: query 'set password = password('')' failed: 1819: Your password does not satisfy the current policy requirements