diff --git a/src/Decoder.php b/src/Decoder.php
index ad44c33..21fc555 100644
--- a/src/Decoder.php
+++ b/src/Decoder.php
@@ -142,7 +142,7 @@ private function processInfinite(Stream $stream, int $mt, bool $breakable): CBOR
             case CBORObject::MAJOR_TYPE_MAP: //5
                 $object = IndefiniteLengthMapObject::create();
                 while (!($it = $this->process($stream, true)) instanceof OtherObject\BreakObject) {
-                    $object->append($it, $this->process($stream, false));
+                    $object->add($it, $this->process($stream, false));
                 }
 
                 return $object;
diff --git a/src/IndefiniteLengthListObject.php b/src/IndefiniteLengthListObject.php
index d86958e..c503697 100644
--- a/src/IndefiniteLengthListObject.php
+++ b/src/IndefiniteLengthListObject.php
@@ -23,6 +23,7 @@
 use IteratorAggregate;
 
 /**
+ * @phpstan-implements ArrayAccess<int, CBORObject>
  * @phpstan-implements IteratorAggregate<int, CBORObject>
  * @final
  */
@@ -141,9 +142,6 @@ public function offsetExists($offset): bool
         return $this->has($offset);
     }
 
-    /**
-     * @param int $offset
-     */
     public function offsetGet($offset): CBORObject
     {
         return $this->get($offset);
diff --git a/src/IndefiniteLengthMapObject.php b/src/IndefiniteLengthMapObject.php
index 4a52b35..d5eea5e 100644
--- a/src/IndefiniteLengthMapObject.php
+++ b/src/IndefiniteLengthMapObject.php
@@ -23,6 +23,7 @@
 use IteratorAggregate;
 
 /**
+ * @phpstan-implements ArrayAccess<int, MapItem>
  * @phpstan-implements IteratorAggregate<int, MapItem>
  * @final
  */
@@ -165,17 +166,11 @@ public function getNormalizedData(bool $ignoreTags = false): array
         return $this->normalize();
     }
 
-    /**
-     * @param int|string $offset
-     */
     public function offsetExists($offset): bool
     {
         return $this->has($offset);
     }
 
-    /**
-     * @param int|string $offset
-     */
     public function offsetGet($offset): MapItem
     {
         return $this->get($offset);
@@ -183,7 +178,7 @@ public function offsetGet($offset): MapItem
 
     public function offsetSet($offset, $value): void
     {
-        if (!$offset instanceof CBORObject && !$offset instanceof Normalizable) {
+        if (!$offset instanceof CBORObject) {
             throw new InvalidArgumentException('Invalid key');
         }
         if (!$value instanceof CBORObject) {
diff --git a/src/ListObject.php b/src/ListObject.php
index 4bee838..6f55db3 100644
--- a/src/ListObject.php
+++ b/src/ListObject.php
@@ -23,6 +23,7 @@
 use IteratorAggregate;
 
 /**
+ * @phpstan-implements ArrayAccess<int, CBORObject>
  * @phpstan-implements IteratorAggregate<int, CBORObject>
  */
 class ListObject extends AbstractCBORObject implements Countable, IteratorAggregate, Normalizable, ArrayAccess
@@ -161,9 +162,6 @@ public function offsetExists($offset): bool
         return $this->has($offset);
     }
 
-    /**
-     * @param int $offset
-     */
     public function offsetGet($offset): CBORObject
     {
         return $this->get($offset);
diff --git a/src/MapObject.php b/src/MapObject.php
index 3c01dd1..890585f 100644
--- a/src/MapObject.php
+++ b/src/MapObject.php
@@ -23,6 +23,7 @@
 use IteratorAggregate;
 
 /**
+ * @phpstan-implements ArrayAccess<int, MapItem>
  * @phpstan-implements IteratorAggregate<int, MapItem>
  */
 final class MapObject extends AbstractCBORObject implements Countable, IteratorAggregate, Normalizable, ArrayAccess
@@ -151,7 +152,7 @@ public function getIterator(): Iterator
     }
 
     /**
-     * @return array<mixed, mixed>
+     * @return array<int|string, mixed>
      */
     public function normalize(): array
     {
@@ -177,17 +178,11 @@ public function getNormalizedData(bool $ignoreTags = false): array
         return $this->normalize();
     }
 
-    /**
-     * @param int|string $offset
-     */
     public function offsetExists($offset): bool
     {
         return $this->has($offset);
     }
 
-    /**
-     * @param int|string $offset
-     */
     public function offsetGet($offset): MapItem
     {
         return $this->get($offset);
@@ -195,7 +190,7 @@ public function offsetGet($offset): MapItem
 
     public function offsetSet($offset, $value): void
     {
-        if (!$offset instanceof CBORObject && !$offset instanceof Normalizable) {
+        if (!$offset instanceof CBORObject) {
             throw new InvalidArgumentException('Invalid key');
         }
         if (!$value instanceof CBORObject) {