diff --git a/src/Collect/Support/Traits/Conditionable.php b/src/Collect/Support/Traits/Conditionable.php
index ee246d4..c985b48 100644
--- a/src/Collect/Support/Traits/Conditionable.php
+++ b/src/Collect/Support/Traits/Conditionable.php
@@ -18,7 +18,7 @@ trait Conditionable
      * @param  (callable($this, TWhenParameter): TWhenReturnType)|null  $default
      * @return $this|TWhenReturnType
      */
-    public function when($value = null, callable $callback = null, callable $default = null)
+    public function when($value = null, ?callable $callback = null, ?callable $default = null)
     {
         $value = $value instanceof Closure ? $value($this) : $value;
 
@@ -50,7 +50,7 @@ public function when($value = null, callable $callback = null, callable $default
      * @param  (callable($this, TUnlessParameter): TUnlessReturnType)|null  $default
      * @return $this|TUnlessReturnType
      */
-    public function unless($value = null, callable $callback = null, callable $default = null)
+    public function unless($value = null, ?callable $callback = null, ?callable $default = null)
     {
         $value = $value instanceof Closure ? $value($this) : $value;