Use function getConcordanceTarget() over direct array access

src/MDConcLengths.php

@@ -9,9 +9,9 @@ declare(strict_types = 1);
 /**
  * Provides lists for categorizing misspelled sizes.
  */
-final class MDConcLengths {
+final class MDConcLengths implements MDImporterConcordanceListInterface {
 
-    const LENGTHS_LIST = [
+    private const LENGTHS_LIST = [
         "cn" => "cm",
         ",cm" => "cm",
         "5cm" => "cm",
@@ -21,4 +21,20 @@ final class MDConcLengths {
         "zoll" => "in",
     ];
 
+    /**
+     * Require a function for getting the concordance target.
+     *
+     * @param string $input Input string.
+     *
+     * @return string
+     */
+    public static function getConcordanceTarget(string $input):string {
+
+        if (!isset(self::LENGTHS_LIST[$input])) {
+            throw new MDImporterMissingConcordance("Unknown length type: " . $input);
+        }
+
+        return self::LENGTHS_LIST[$input];
+
+    }
 }