text: const utils = {};
  module.exports = utils;
  
  /**
   * Check whether passed argument is an array
   * @param {any} arr
   * @returns {boolean}
   */
  utils.isArray = arr => Array.isArray(arr);
  
  /**
   * Check whether passed argument is an array
   * @param {any} obj
   * @returns {boolean}
   */
  utils.isObject = obj => !utils.isArray(obj) && (obj !== null) && (typeof obj === 'object');
  
  /**
   * Check whether passed argument is a function
   * @param {Function} f
   * @returns {boolean}
   */
  utils.isFunc = f => typeof f === 'function';
  utils.isFunction = utils.isFunc;
  
  /**
   * Check whether passed argument is a string
   * @param {String} str
   * @returns {boolean}
   */
  utils.isString = str => typeof str === 'string';
  