with_scope_level

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 1390
          def with_scope_level(kind, resource = parent_resource)
            old, @scope[:scope_level] = @scope[:scope_level], kind
            old_resource, @scope[:scope_level_resource] = @scope[:scope_level_resource], resource
            yield
          ensure
            @scope[:scope_level] = old
            @scope[:scope_level_resource] = old_resource
          end