code: public static ContextAwarePolicy createDefaultPolicy(PublicationsHandler handler, Extender extender) {
          Util.notNull(handler, "Publications handler");
          return new ContextAwarePolicyAdapter(new DefaultVerificationPolicy(),
                  new PolicyContext(handler, extender != null ? extender.getExtendingService() : null));
      }
docs: Creates context aware policy using {@link DefaultVerificationPolicy} for verification.
  If extender is set, signature is extended within verification process.
  
  @param handler
  Publications handler.
  @param extender
  Extender.
  @return Context aware verification policy for default verification.