code: function(requestId, exceptionMessage, exceptionType) {
  		if (exceptionType === "subscription") {
  			return protocol.implodeMessage(requestId, dataMethods.UNSUBSCRIBE,
  				exceptions.SUBSCRIPTION, protocol.encodeString(exceptionMessage));
  		} else {
  			return protocol.implodeMessage(requestId, dataMethods.UNSUBSCRIBE,
  				exceptions.GENERIC, protocol.encodeString(exceptionMessage));
  		}
  	}
docs: Encodes an unsuccessful unsubscribe reply.
  
  @param {String} requestId the originating request id
  @param {String} exceptionMessage the exception message
  @param {String} [exceptionType] the exception type. Allowed values: subscription
  @return {String} the encoded message
  @private