attachEvent(sType, fnFunction, oData) {
			assert(typeof (sType) === "string" && sType, "Eventing.attachEvent: sType must be a non-empty string");
			assert(typeof (fnFunction) === "function", "Eventing.attachEvent: fnFunction must be a function");

			let aEventListeners = this.#mEventRegistry[sType];
			if ( !Array.isArray(aEventListeners) ) {
				aEventListeners = this.#mEventRegistry[sType] = [];
			}

			aEventListeners.push({fnFunction: fnFunction, oData: oData});
		}
Attaches an event handler to the event with the given identifier.

@param {string}
		sType The type of the event to listen for
@param {function}
		fnFunction The handler function to call when the event occurs. The event
		object ({@link module:sap/base/Event}) is provided as first argument of the handler. Handlers must not change
		the content of the event.
@param {object}
		[oData] An object that will be passed to the handler along with the event object when the event is fired
@since 1.120.0
@private
@ui5-restricted sap.ui.core sap/base/i18n