code: def getMaintenanceTypes(self):
          
          types = [('Preventive',safe_unicode(_('Preventive')).encode('utf-8')),
                   ('Repair', safe_unicode(_('Repair')).encode('utf-8')),
                   ('Enhancement', safe_unicode(_('Enhancement')).encode('utf-8'))]
          return DisplayList(types)
docs: Return the current list of maintenance types