code: function saveSettings( state = false, { type } ) {
  	switch ( type ) {
  		case WOOCOMMERCE_MAILCHIMP_SAVE_SETTINGS:
  			return true;
  		case WOOCOMMERCE_MAILCHIMP_NEWSLETTER_SETTINGS_SUBMIT_SUCCESS:
  		case WOOCOMMERCE_MAILCHIMP_NEWSLETTER_SETTINGS_SUBMIT_FAILURE:
  			return false;
  	}
  
  	return state;
  }
docs: Updates state with save settings request status
  The name ( saveSettings ) is generic because in future this should repond
  also to other events than newsletter settings
  
  @param  {Object} state  Current state
  @param  {Object} action Action
  @return {Object}        Updated state