code: public boolean isValidTld(String tld) {
          tld = unicodeToASCII(tld);
          if(allowLocal && isValidLocalTld(tld)) {
              return true;
          }
          return isValidInfrastructureTld(tld)
                  || isValidGenericTld(tld)
                  || isValidCountryCodeTld(tld);
      }
docs: Returns true if the specified <code>String</code> matches any
  IANA-defined top-level domain. Leading dots are ignored if present.
  The search is case-insensitive.
  @param tld the parameter to check for TLD status, not null
  @return true if the parameter is a TLD