import { BuilderFunction } from './Types';
/**
 * A {@link BuilderFunction} implementation.
 *
 * Produces a string representation of the tree
 * for testing and debug purposes.
 *
 * Only accepts `string` as the associated value type.
 * Map your input collection before creating a {@link DecisionTree}
 * if you want to use it with a different type -
 * the decision on how to stringify the value is up to you.
 *
 * @param nodes - nodes from the root level of the decision tree.
 * @returns the string representation of the tree.
 */
export declare const treeify: BuilderFunction<string, string>;