This is the traceback:

Just checked in psql:
create schema "Hello";
select 'Hello'::regnamespace; -- error
select "Hello"::regnamespace; -- error
select '"Hello"'::regnamespace; -- works
So we'll just need to wrap the schema name in double quotes and then single quotes... see also:
https://dba.stackexchange.com/questions/234330/how-to-use-to-regclass-with-uppercase-table-names