addCustomCurrencies(mCurrencies) {
			const mExistingCurrencies = Formatting.getCustomCurrencies();
			if (mExistingCurrencies){
				mCurrencies = extend({}, mExistingCurrencies, mCurrencies);
			}
			Formatting.setCustomCurrencies(mCurrencies);
		}
Adds custom currencies. There is a special currency code named "DEFAULT" that is optional. In case it is set
it is used for all currencies not contained in the list, otherwise currency digits as defined by the CLDR are
used as a fallback.

<b>Note:</b> Adding custom currencies affects all applications running with the current UI5 core instance.
@param {Object<string,module:sap/base/i18n/Formatting.CustomCurrency>} [mCurrencies]
  A map with the currency code as key and a custom currency definition as value; already existing custom
  currencies are replaced, new ones are added; the custom currency code must contain at least one non-digit
  character, so that the currency part can be distinguished from the amount part; see
  {@link #.getCustomCurrencies Formatting.getCustomCurrencies} for an example

@public
@since 1.120