diff -r 251d0ed461fb -r 58ec6da75f6f task4/solution06/src/org/apidesign/apifest08/currency/Assert.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/task4/solution06/src/org/apidesign/apifest08/currency/Assert.java	Sat Oct 11 23:38:46 2008 +0200
@@ -0,0 +1,11 @@
+package org.apidesign.apifest08.currency;
+
+public final class Assert {
+	static void notNull(Object value, String argumentName) {
+		if(value == null) {
+			throw new IllegalArgumentException("The argument '" + argumentName + "' connot not be null");
+		}
+	}
+}
+
+