Returns an {@code InternetDomainName} that is the immediate ancestor ofthis one; that is, the current domain with the leftmost part removed. For example, the parent of {@code www.google.com} is {@code google.com}.
@throws IllegalStateException if the domain has no parent, as determinedby {@link #hasParent}
All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.