code: function createResponseHandler(fn, key, context) {
  	// Assert.func(fn,'createResponseHandler:fn')
  	return function (props) {
  		const param = key ? props[key] : props
  		print(fn(param), props, context)
  	}
  }
docs: Creates an async response handler
  
  @param {function} fn - function to be called
  @param {string} [key] - function will be called with props[key] if not specified, the function will be called with the props object
  @param {object} [context] - handlers used in print
  @returns