code: def get_default_redirect(self, rule, method, values, query_args):
          
          assert self.map.redirect_defaults
          for r in self.map._rules_by_endpoint[rule.endpoint]:
              # every rule that comes after this one, including ourself
              # has a lower priority for the defaults.  We order the ones
              # with the highest priority up for building.
              if r is rule:
                  break
              if r.provides_defaults_for(rule) and r.suitable_for(values, method):
                  values.update(r.defaults)
                  domain_part, path = r.build(values)
                  return self.make_redirect_url(path, query_args, domain_part=domain_part)
docs: A helper that returns the URL to redirect to if it finds one.
          This is used for default redirecting only.
  
          :internal: