src/main/java/org/xmlet/xsdparser/xsdelements/XsdGroup.java
private void rule3() {
        if (parent instanceof XsdSchema && name == null){
            throw new ParsingException(XSD_TAG + " element: The " + NAME_TAG + " should is required the parent of the " + XSD_TAG + " is the " + XsdSchema.XSD_TAG + " element." );
        }
    }
private void rule3() {
        if (parent instanceof XsdSchema && name == null){
            throw new ParsingException(XSD_TAG + " element: The " + NAME_TAG + " should is required the parent of the " + XSD_TAG + " is the " + XsdSchema.XSD_TAG + " element." );
        }
    }
Asserts if the current has no value for its name attribute while being a direct child of the top level XsdSchema element,
which is required. Throws an exception if no name is present.