docs: public void clearUnknowns(ValidationObject object)
  	{
  		ObjectMetadata objectMetadata = object.getMetadata();
  		ValidationSession session = object.getMetadata().getProxyObject().getSession();
  		session.setEnabled(false);
  		Map<String,ProxyField> fieldMap = objectMetadata.getProxyObject().getFieldMap();
  		for (Map.Entry<String,ProxyField> entry: fieldMap.entrySet())
  		{
  			FieldMetadata fieldMetadata = entry.getValue().getFieldMetadata();
  			ProxyFieldImpl proxyField = (ProxyFieldImpl)session.getProxyField(fieldMetadata);
  			if (proxyField.getPropertyMetadata().isUnknown()) // this tests the static unknown flag
  			{
  				// force the value to null and then set the dynamic unknown flag
  				proxyField.reset();
  				proxyField.setValue(null);
  				proxyField.updateValue();
  				proxyField.setUnknown(true);
  				logger.debug("Cleared {}",proxyField.toString());
  			}
  		}
  		session.setEnabled(true);
  	}