diff --git a/Resources/config/services.xml b/Resources/config/services.xml
index ba74ff37..80e876e7 100644
--- a/Resources/config/services.xml
+++ b/Resources/config/services.xml
@@ -40,7 +40,7 @@
         <parameter key="jms_serializer.xml_serialization_visitor.class">JMS\Serializer\XmlSerializationVisitor</parameter>
         <parameter key="jms_serializer.xml_deserialization_visitor.class">JMS\Serializer\XmlDeserializationVisitor</parameter>
         <parameter key="jms_serializer.xml_deserialization_visitor.doctype_whitelist" type="collection"></parameter>
-        <parameter key="jms_serializer.xml_serialization_visitor.format_output" type="collection"></parameter>
+        <parameter key="jms_serializer.xml_serialization_visitor.format_output"></parameter>
         <parameter key="jms_serializer.yaml_serialization_visitor.class">JMS\Serializer\YamlSerializationVisitor</parameter>
         
         <parameter key="jms_serializer.handler_registry.class">JMS\Serializer\Handler\LazyHandlerRegistry</parameter>