code: def service_table(format='simple', authenticated=False):
      
      if authenticated:
          all_services = ExchangeUniverse.get_authenticated_services()
      else:
          all_services = ALL_SERVICES
  
      if format == 'html':
          linkify = lambda x: "<a href='{0}' target='_blank'>{0}</a>".format(x)
      else:
          linkify = lambda x: x
  
      ret = []
      for service in sorted(all_services, key=lambda x: x.service_id):
          ret.append([
              service.service_id,
              service.__name__, linkify(service.api_homepage.format(
                  domain=service.domain, protocol=service.protocol
              )),
              ", ".join(service.supported_cryptos or [])
          ])
  
      return tabulate(ret, headers=['ID', 'Name', 'URL', 'Supported Currencies'], tablefmt=format)
docs: Returns a string depicting all services currently installed.