private String getQualifier(final Map<String, Object> client) {
        if (Objects.isNull(client)) {
            return null;
        }
        String qualifier = (String) client.get("qualifier");
        if (StringUtils.hasText(qualifier)) {
            return qualifier;
        }
        return null;
    }
Gets base packages.
@param importingClassMetadata the importing class metadata
@return the base packages
shenyu-sdk/shenyu-sdk-feign/src/main/java/org/apache/shenyu/sdk/feign/ShenyuClientsRegistrar.java