Complex Row Level Filter is not getting expected results as create function is failed

condition: country in (SELECT country from sample_view WHERE name=‘test’)

query:
CREATE OR REPLACE FUNCTION sv_test_space_1_sample_view (country varchar, name varchar)
RETURNS BOOLEAN
RETURN SELECT CASE WHEN
(
(country in (SELECT country from test_space_1.sample_view WHERE name=‘test’))
AND
(is_member(‘user_test_1’) OR is_member(‘group_test_1’) OR is_member(‘role_test_1’) )
)
OR
(
(not is_member(‘user_test_1’)
AND not is_member(‘group_test_1’)
AND not is_member(‘role_test_1’)
)
)
THEN true ELSE false END;