# File lib/ruote/exp/ro_on_x.rb, line 143
      def update_tree(tree, retries)

        child = tree[2][@child_id]

        if @pattern
          if retries.empty?
            child[1].delete(@pattern)
          else
            child[1][@pattern] = retries.join(', ')
          end
        else
          key, _ = child[1].find { |k, v| v.nil? }
          child[1].delete(key)
          child[1][retries.join(', ')] = nil if retries.any?
        end
      end