function prettyFunctionName()
    {
        return "String.format(\"" + format + "\", \"" + Array.prototype.join.call(substitutions, "\", \"") + "\")";
    }
@param {string} format
@param {?ArrayLike} substitutions
@param {!Object.<string, function(string, ...):string>} formatters
@param {!T} initialValue
@param {function(T, string): T|undefined} append
@param {!Array.<!Object>=} tokenizedFormat
@return {!{formattedResult: T, unusedSubstitutions: ?ArrayLike}};
@template T