Instruction
Awesome! The extract_mailing_list() has been created, so let's run a final quick test and invoke the function.
Exercise
Invoke the extract_mailing_list() function (so that we have multiple columns).

Awesome! The extract_mailing_list() has been created, so let's run a final quick test and invoke the function.
Invoke the extract_mailing_list() function (so that we have multiple columns).
