diff --git a/Model/Resolver/AddressDetails.php b/Model/Resolver/AddressDetails.php
index f336c82..76cac45 100644
--- a/Model/Resolver/AddressDetails.php
+++ b/Model/Resolver/AddressDetails.php
@@ -41,8 +41,8 @@ public function resolve(
         Field $field,
               $context,
         ResolveInfo $info,
-        array $value = null,
-        array $args = null
+        ?array $value = null,
+        ?array $args = null
     ) {
 
         if (!isset($args['context']) || !$args['context']) {
diff --git a/Model/Resolver/Autocomplete.php b/Model/Resolver/Autocomplete.php
index 75de994..795db7f 100644
--- a/Model/Resolver/Autocomplete.php
+++ b/Model/Resolver/Autocomplete.php
@@ -1,4 +1,4 @@
-<?php
+ull<?php
 
 /**
  * A Magento 2 module named Experius/Postcode
@@ -53,8 +53,8 @@ public function resolve(
         Field $field,
               $context,
         ResolveInfo $info,
-        array $value = null,
-        array $args = null
+        ?array $value = null,
+        ?array $args = null
     ) {
         if (!isset($args['countryId']) || !$args['countryId']) {
             throw new GraphQlInputException(__('"countryId" should be specified'));
diff --git a/Model/Resolver/Postcode.php b/Model/Resolver/Postcode.php
index 2facfaf..4e57ec7 100644
--- a/Model/Resolver/Postcode.php
+++ b/Model/Resolver/Postcode.php
@@ -45,8 +45,8 @@ public function resolve(
         Field $field,
         $context,
         ResolveInfo $info,
-        array $value = null,
-        array $args = null
+        ?array $value = null,
+        ?array $args = null
     ) {
         if (!isset($args['postcode']) || !$args['postcode']) {
             throw new GraphQlInputException(__('"postcode" should be specified'));