async def METHOD_NAME(term_id, class_number):
	'''Return the business emails of instructors for courses matching
	   {term_id} and {class_number.'''
	# get the instructors of our course. sis only has their uids, not emails.
	uids = await classes.get_instructors(
		SIS_CLASSES_ID, SIS_CLASSES_KEY,
		term_id, class_number, include_secondary='true'
	)
	# ask hr for the emails
	emails = set()
	for uid in uids:
		# get all emails
		items = await ucbhr_info.get(UCB_HR_ID, UCB_HR_KEY, uid, 'campus-uid')
		# extract the business (berkeley.edu) addresses
		hr_emails = set(ucbhr_info.emails(items, 'BUSN'))
		emails |= hr_emails
		logger.debug(f"HR emails: {hr_emails}")
		# also look up their student emails in SIS; students' emails
		# aren't in HR apparently, even if they're employed as GSIs
		sis_emails = set(
			await student.get_emails(SIS_STUDENTS_ID, SIS_STUDENTS_KEY, uid)
		)
		logger.debug(f"SIS emails: {sis_emails}")
		emails |= sis_emails
	return emails