* <p>
* The following outlines suggested values as defined by netconf (<a href="https://tools.ietf.org/html/rfc6241#page-89">RFC 6241</a>):
* <pre>
- * access_denied
- * bad_attribute
- * bad_element
- * data_exists
- * data_missing
- * in_use
- * invalid_value
- * lock_denied
- * malformed_message
- * missing_attribute
- * missing_element
- * operation_failed
- * operation_not_supported
- * resource_denied
- * rollback_failed
- * too_big
- * unknown_attribute
- * unknown_element
- * unknown_namespace
+ * access-denied
+ * bad-attribute
+ * bad-element
+ * data-exists
+ * data-missing
+ * in-use
+ * invalid-value
+ * lock-denied
+ * malformed-message
+ * missing-attribute
+ * missing-element
+ * operation-failed
+ * operation-not-supported
+ * resource-denied
+ * rollback-failed
+ * too-big
+ * unknown-attribute
+ * unknown-element
+ * unknown-namespace
* </pre>
* @return a string if available or null otherwise.
*/