getCustomUnits() {
			return mSettings["units"]?.["short"];
		}
Gets the custom units that have been set via {@link #.addCustomUnits Formatting.addCustomUnits} or
{@link #.setCustomUnits Formatting.setCustomUnits}.

@returns {Object<string,module:sap/base/i18n/Formatting.CustomUnit>|undefined}
  A map with the unit code as key and a custom unit definition containing a display name and different unit
  patterns as value; or <code>undefined</code> if there are no custom units

@public
@example <caption>A simple custom type "BAG" for which the value <code>1</code> is formatted as "1 bag", for
  example in locale 'en', while <code>2</code> is formatted as "2 bags"</caption>
{
  "BAG": {
    "displayName": "Bag",
    "unitPattern-count-one": "{0} bag",
    "unitPattern-count-other": "{0} bags"
  }
}
@since 1.123