    # File lib/chef/exceptions.rb, line 142
            def to_json(*a)
              result = {
                "message" => message,
                "unsatisfiable_run_list_item" => run_list_item,
                "non_existent_cookbooks" => non_existent_cookbooks,
                "most_constrained_cookbooks" => most_constrained_cookbooks
              }
              result.to_json(*a)
            end