code: function PropertyCache(oRequestor, sResourcePath, mQueryOptions) {
  		Cache.call(this, oRequestor, sResourcePath, mQueryOptions);
  
  		this.oPromise = null;
  	}
docs: ********************************************************************************************* PropertyCache ********************************************************************************************* 
  Creates a cache for a single property that performs requests using the given requestor.
  
  @param {sap.ui.model.odata.v4.lib._Requestor} oRequestor
  The requestor
  @param {string} sResourcePath
  A resource path relative to the service URL
  @param {object} [mQueryOptions]
  A map of key-value pairs representing the query string