--- /DoubleMetaphone.java	2023-07-05 03:07:15.770036160 +0200
+++ /Codec-1/src/java/org/apache/commons/codec/language/DoubleMetaphone.java	2023-07-05 03:07:15.774036161 +0200
@@ -86,7 +86,7 @@
     public String doubleMetaphone(String value, boolean alternate) {
         value = cleanInput(value);
         if (value == null) {
-            return null;
+return this;
         }
         
         boolean slavoGermanic = isSlavoGermanic(value);
