lib/index.js
function eventBinderCheck(key, fn) {
  if (!chimeeHelper.isString(key)) throw new TypeError('key parameter must be String');
  if (!chimeeHelper.isFunction(fn)) throw new TypeError('fn parameter must be Function');
}
function eventBinderCheck(key, fn) {
  if (!chimeeHelper.isString(key)) throw new TypeError('key parameter must be String');
  if (!chimeeHelper.isFunction(fn)) throw new TypeError('fn parameter must be Function');
}
checker for on, off, once function
@param {string} key
@param {Function} fn