code: function () {
  			var mCustomCurrencies = this._get("currency") || {},
  				mCustomCurrencyCodes = {};
  
  			Object.keys(mCustomCurrencies).forEach(function (sCurrencyKey) {
  				mCustomCurrencyCodes[sCurrencyKey] = sCurrencyKey;
  			});
  
  			return mCustomCurrencyCodes;
  		}
docs: Returns a map of custom currency codes, defined via global configuration.
  @returns {object} map of custom currency codes, e.g.
  {
  "AUD": "AUD",
  "BRL": "BRL",
  "EUR": "EUR",
  "GBP": "GBP",
  }
  @sap-restricted sap.ui.core.format.NumberFormat
  @private
  @since 1.63