function messageBoxPromise(sMessageType, sMessage, mOptions) {
		return new Promise(function(resolve) {
			mOptions.onClose = resolve;
			MessageBox[sMessageType](sMessage, mOptions);
		});
	}
Shows a message box of the specified type; The message consists of the evaluated messagekey and an error text if provided;
The titlekey in the mPropertyBag is also evaluated, the rest is passed to the {@link sap.m.MessageBox} constructor.

@param  {string} sMessageType - The type of the message box; See available types in {@link sap.m.MessageBox}
@param  {string} sMessageKey - The text key for the message of the message box
@param  {object} [mPropertyBag] - Object with additional information; error and titleKey are evaluated, the rest is passed as option to the MessageBox
@param  {any} [mPropertyBag.error] - If an error is passed on, the message box text is derived from it
@param  {string} [mPropertyBag.titleKey] - The text key for the title of the message box; if none is provided the default of the selectde MessageBox type  will be displayed
@param  {array} [mPropertyBag.actions] - Available actions for the messabe box
@param  {array} [mPropertyBag.actionKeys] - The text key for the action buttons of the message box. It is provided as actions property to the MessageBox.
											   If mPropertyBag.actions property is set, it will not be overriden
@param {string} [mPropertyBag.emphasizedAction] - Action option to be emphasized
@param {string} [mPropertyBag.emphasizedActionKey] - Text key of the action option to be emphasized
@param {boolean} [mPropertyBag.showCancel] - Whether "cancel" should be part of the actions
@returns{Promise} Promise displaying the message box; resolves when it is closed with the pressed button