refactor firewall/auto_allow_signed_applications to use ensure, default arg, and validate arg
refactor firewall/block_all_incoming_connections to use ensure, default arg, and validate arg
refactor firewall/logging_mode to use ensure, default arg, and validate arg
refactor firewall/stealth_mode to use ensure, default arg, and validate arg
refactor itunes/automatic_device_backup_when_syncing to use ensure, default arg, and validate arg
refactor itunes/automatic_sync to use ensure, default arg, and validate arg
refactor keyboard/accented_press_and_hold to use ensure, default arg, and validate arg
refactor keyboard/autocorrect to use ensure, default arg, and validate arg
typos
refactor keyboard/control_access to use ensure, default arg, and validate arg
refactor keyboard/default_to_alternate_function_keys to use ensure, default arg, and validate arg
refactor keyboard/illumination to use ensure, default arg, and validate arg
validate arg
validate arg
refactor login/admin_information to use ensure, default arg, and validate arg
refactor login/auto_login to use ensure, default arg, and validate arg
refactor login/fast_user_switching to use ensure, default arg, and validate arg
refactor login/guest to use ensure, default arg, and validate arg
refactor login/power_options to use ensure, default arg, and validate arg
default arg