Outside of running jobs with different users, is there any way for me to run a notebook (or even better a cell within a notebook) as either a different user or a specific role that is not my user default?

I'm trying to find an easy way to test data masking functions with something like this:

set user or rule to be one without elevated privileges;
select SSN from table;
If SSN = '********' then pass the test;
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set user or rule to be one with elevated privileges;
select SSN from table;
If SSN = '123456789' then pass the test;