"Required classes" refers to the courses or subjects that you must take or attend in order to meet certain educational or program requirements. Full definition
If learners have significant prior knowledge of a subject, they may place out of required classes through «challenge testing»: passing end - of - course exams without attending any classes. (ascd.org)
If you enroll in either of the two traffic course offerings at a traditional driving school, your attendance must meet the minimum required class time. (myimprov.com)
Some municipalities require a class even if there is not a state law requiring it. (thespruce.com)