diff --git a/accessibility-rs/src/engine/audit/wcag.rs b/accessibility-rs/src/engine/audit/wcag.rs
index 5543fee..0f54a48 100644
--- a/accessibility-rs/src/engine/audit/wcag.rs
+++ b/accessibility-rs/src/engine/audit/wcag.rs
@@ -36,7 +36,7 @@ impl WCAGAAA {
                                         "WCAGAAA",
                                         rule.principle.as_str(),
                                         rule.guideline.as_str(),
-                                        rule.rule_id.as_str(),
+                                        &rule.rule_id.into_str(),
                                     ]
                                     .join("."),
                                     rule.issue_type.as_str(),
diff --git a/accessibility-rs/src/engine/rules/rule.rs b/accessibility-rs/src/engine/rules/rule.rs
index 5e52977..f4d8564 100644
--- a/accessibility-rs/src/engine/rules/rule.rs
+++ b/accessibility-rs/src/engine/rules/rule.rs
@@ -37,11 +37,47 @@ impl Validation {
     }
 }
 
+#[derive(Debug, Clone)]
+/// techniques for a rule
+pub enum Technique {
+    /// a single technique
+    Single(Techniques),
+    /// multiple techniques
+    Multi(Vec<Techniques>),
+}
+
+impl Technique {
+    /// technique(s) into string
+    pub fn into_str(&self) -> String {
+        match self {
+            Technique::Multi(tech) => tech
+                .iter()
+                .map(|x| x.as_str())
+                .collect::<Vec<_>>()
+                .join(",")
+                .into(),
+            Technique::Single(tech) => tech.as_str().into(),
+        }
+    }
+}
+
+impl From<Techniques> for Technique {
+    fn from(t: Techniques) -> Self {
+        Technique::Single(t)
+    }
+}
+
+impl From<Vec<Techniques>> for Technique {
+    fn from(t: Vec<Techniques>) -> Self {
+        Technique::Multi(t)
+    }
+}
+
 /// the rule validation method that should be performed.
 #[derive(Debug)]
 pub struct Rule {
     /// the message id of the rule to point to the locale
-    pub rule_id: Techniques,
+    pub rule_id: Technique,
     /// the type of rule
     pub issue_type: IssueType,
     /// validate a test returns (valid, rule, selectors)
@@ -57,7 +93,7 @@ pub struct Rule {
 impl Rule {
     /// a new rule type
     pub fn new(
-        rule_id: Techniques,
+        rule_id: Technique,
         issue_type: IssueType,
         principle: Principle,
         guideline: Guideline,
diff --git a/accessibility-rs/src/engine/rules/techniques.rs b/accessibility-rs/src/engine/rules/techniques.rs
index e2c0ca5..7405fe9 100644
--- a/accessibility-rs/src/engine/rules/techniques.rs
+++ b/accessibility-rs/src/engine/rules/techniques.rs
@@ -1,6 +1,6 @@
 use strum_macros::IntoStaticStr;
 
-#[derive(PartialOrd, Ord, std::cmp::Eq, PartialEq, Hash, Debug, IntoStaticStr)]
+#[derive(PartialOrd, Ord, std::cmp::Eq, PartialEq, Hash, Debug, IntoStaticStr, Clone)]
 /// techniques for WCAG <https://www.w3.org/TR/WCAG20-TECHS/>
 pub enum Techniques {
     /// <https://www.w3.org/TR/WCAG20-TECHS/H25>
diff --git a/accessibility-rs/src/engine/rules/wcag_rule_map.rs b/accessibility-rs/src/engine/rules/wcag_rule_map.rs
index b72df7c..0adc4b0 100644
--- a/accessibility-rs/src/engine/rules/wcag_rule_map.rs
+++ b/accessibility-rs/src/engine/rules/wcag_rule_map.rs
@@ -16,11 +16,11 @@ lazy_static! {
     pub static ref RULES_A: BTreeMap<&'static str, Vec<Rule>> =
         vec![
             ("html", Vec::from([
-                Rule::new(Techniques::H57, IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H57.into(), IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
                     let n = nodes[0].0;
                     Validation::new_issue(!n.attr("lang").unwrap_or_default().is_empty() || !n.attr("xml:lang").unwrap_or_default().is_empty(), "2")
                 }),
-                Rule::new(Techniques::H57, IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H57.into(), IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
                     let lang = nodes[0].0.attr("lang").unwrap_or_default();
                     let alphabetic = lang.chars().all(|x| x.is_alphabetic());
                     // <https://www.rfc-editor.org/rfc/bcp/bcp47.txt>
@@ -32,7 +32,7 @@ lazy_static! {
                         alphabetic && lang.len() < 12
                     }, "3.Lang")
                 }),
-                Rule::new(Techniques::H57, IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H57.into(), IssueType::Error, Principle::Understandable, Guideline::Readable, "1", |nodes, _lang| {
                     let lang = nodes[0].0.attr("xml:lang").unwrap_or_default();
                     let alphabetic = lang.chars().all(|x| x == '_' || x.is_alphabetic());
                    // <https://www.rfc-editor.org/rfc/bcp/bcp47.txt>
@@ -44,7 +44,7 @@ lazy_static! {
                         alphabetic && lang.len() < 12
                     }, "3.XmlLang")
                 }),
-                Rule::new(Techniques::F77, IssueType::Error, Principle::Robust, Guideline::Compatible, "1", |nodes, lang| {
+                Rule::new(Techniques::F77.into(), IssueType::Error, Principle::Robust, Guideline::Compatible, "1", |nodes, lang| {
                    let mut id_map: HashMap<&str, u8> = HashMap::new();
                    let mut valid = true;
 
@@ -84,7 +84,7 @@ lazy_static! {
                 }),
             ])),
             ("meta", Vec::from([
-                Rule::new(Techniques::F40, IssueType::Error, Principle::Operable, Guideline::EnoughTime, "1", |nodes, _lang| {
+                Rule::new(Techniques::F40.into(), IssueType::Error, Principle::Operable, Guideline::EnoughTime, "1", |nodes, _lang| {
                     let mut valid = true;
 
                     for node in nodes {
@@ -100,7 +100,7 @@ lazy_static! {
 
                     Validation::new_issue(valid, "2")
                 }),
-                Rule::new(Techniques::F41, IssueType::Error, Principle::Understandable, Guideline::EnoughTime, "1", |nodes, _lang| {
+                Rule::new(Techniques::F41.into(), IssueType::Error, Principle::Understandable, Guideline::EnoughTime, "1", |nodes, _lang| {
                     let mut valid = true;
 
                     for node in nodes {
@@ -118,30 +118,30 @@ lazy_static! {
                 }),
             ])),
             ("title", Vec::from([
-                Rule::new(Techniques::H25, IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H25.into(), IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
                     Validation::new_issue(!nodes.is_empty(), "1.NoTitleEl")
                 }),
-                Rule::new(Techniques::H25, IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H25.into(), IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
                     Validation::new_issue(nodes.is_empty() || nodes[0].0.html().is_empty(), "1.EmptyTitle")
                 }),
             ])),
             ("blink", Vec::from([
-                Rule::new(Techniques::F47, IssueType::Error, Principle::Operable, Guideline::EnoughTime, "2", |nodes, _lang| {
+                Rule::new(Techniques::F47.into(), IssueType::Error, Principle::Operable, Guideline::EnoughTime, "2", |nodes, _lang| {
                     Validation::new_issue(nodes.is_empty(), "")
                 }),
             ])),
             ("iframe", Vec::from([
-                Rule::new(Techniques::H64, IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H64.into(), IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
                     validate_missing_attr(nodes, "title", "1")
                 }),
             ])),
             ("frame", Vec::from([
-                Rule::new(Techniques::H64, IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H64.into(), IssueType::Error, Principle::Operable, Guideline::Navigable, "1", |nodes, _lang| {
                     validate_missing_attr(nodes, "title", "1")
                 }),
             ])),
             ("form", Vec::from([
-                Rule::new(Techniques::H32, IssueType::Error, Principle::Operable, Guideline::Predictable, "2", |nodes, _lang| {
+                Rule::new(Techniques::H32.into(), IssueType::Error, Principle::Operable, Guideline::Predictable, "2", |nodes, _lang| {
                     let mut valid = false;
                     let mut elements = Vec::new();
                     let selector = unsafe { Selector::parse("button[type=submit]").unwrap_unchecked() };
@@ -161,7 +161,7 @@ lazy_static! {
 
                     Validation::new(valid, "2", elements, Default::default())
                 }),
-                Rule::new(Techniques::H36, IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
+                Rule::new(Techniques::H36.into(), IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
                     let mut valid = false;
                     let mut elements = Vec::new();
                     let selector = unsafe { Selector::parse("input[type=image][name=submit]").unwrap_unchecked() };
@@ -183,7 +183,7 @@ lazy_static! {
                 }),
             ])),
             ("a", Vec::from([
-                Rule::new(Techniques::H30, IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
+                Rule::new(Techniques::H30.into(), IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
                     let mut valid = true;
                     let selector = unsafe { Selector::parse("img").unwrap_unchecked() };
                     let mut elements = Vec::new();
@@ -203,7 +203,7 @@ lazy_static! {
 
                     Validation::new(valid, "2", elements, Default::default())
                 }),
-                Rule::new(Techniques::H91, IssueType::Error, Principle::Robust, Guideline::Compatible, "2", |nodes, _lang| {
+                Rule::new(Techniques::H91.into(), IssueType::Error, Principle::Robust, Guideline::Compatible, "2", |nodes, _lang| {
                     let mut valid = true;
                     let mut elements = Vec::new();
 
@@ -222,7 +222,7 @@ lazy_static! {
                     }
                     Validation::new(valid, "A.NoContent", elements, Default::default())
                 }),
-                Rule::new(Techniques::H91, IssueType::Error, Principle::Robust, Guideline::Compatible, "2", |nodes, _lang| {
+                Rule::new(Techniques::H91.into(), IssueType::Error, Principle::Robust, Guideline::Compatible, "2", |nodes, _lang| {
                     let mut valid = true;
                     let mut elements = Vec::new();
                     for ele in nodes {
@@ -237,7 +237,7 @@ lazy_static! {
                 }),
             ])),
             ("img", Vec::from([
-                Rule::new(Techniques::H37, IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
+                Rule::new(Techniques::H37.into(), IssueType::Error, Principle::Perceivable, Guideline::TextAlternatives, "1", |nodes, _lang| {
                     let mut valid = true;
                     let mut elements = Vec::new();
 
@@ -254,32 +254,32 @@ lazy_static! {
                 }),
             ])),
             ("h1", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
             ("h2", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
             ("h3", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
             ("h4", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
             ("h5", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
             ("h6", Vec::from([
-                Rule::new(Techniques::H42, IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
+                Rule::new(Techniques::H42.into(), IssueType::Error, Principle::Perceivable, Guideline::Adaptable, "1", |nodes, _lang| {
                     validate_empty_nodes(nodes, "2")
                 }),
             ])),
diff --git a/accessibility-rs/src/i18n/locales.rs b/accessibility-rs/src/i18n/locales.rs
index 8f2e3bd..5e4fd8b 100644
--- a/accessibility-rs/src/i18n/locales.rs
+++ b/accessibility-rs/src/i18n/locales.rs
@@ -84,7 +84,7 @@ pub fn get_message_i18n_str_raw(
 pub fn get_message_i18n_str(rule: &Rule, section: &str) -> String {
     get_message_i18n_str_raw(
         &rule.guideline,
-        rule.rule_id.as_str(),
+        &rule.rule_id.into_str(),
         rule.success_criteria,
         section,
     )
diff --git a/accessibility-rs/tests/unit/html.rs b/accessibility-rs/tests/unit/html.rs
index 4722457..11f233f 100644
--- a/accessibility-rs/tests/unit/html.rs
+++ b/accessibility-rs/tests/unit/html.rs
@@ -27,7 +27,6 @@ fn _audit_duplicate_element_id() {
     assert_eq!(valid, false)
 }
 
-
 #[test]
 /// duplicate html elements with locale "ja"
 fn _audit_duplicate_element_id_ja() {
@@ -41,9 +40,9 @@ fn _audit_duplicate_element_id_ja() {
         <div id="dog"></div>
     </body> 
  </html>"###,
- "",
-      false,
-      "ja"
+        "",
+        false,
+        "ja",
     ));
     let mut valid = true;