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');
}
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
checker for on off once function