diff --git a/src/Carbon.php b/src/Carbon.php
index 55d8c54..7ed7cab 100644
--- a/src/Carbon.php
+++ b/src/Carbon.php
@@ -13,7 +13,7 @@ class Carbon extends CarbonBase
 {
     const MONTHS_PER_HALF = 6;
 
-    public function __get($name)
+    public function __get(string $name): mixed
     {
        switch ($name) {
             case 'half':
@@ -57,7 +57,7 @@ class Carbon extends CarbonBase
      *
      * @return static
      */
-    public function startOfHalf($dayOfWeek = null)
+    public function startOfHalf(int $dayOfWeek=NULL)
     {
         return $this->setDate($this->year, $this->half * static::MONTHS_PER_HALF - 5, 1)->firstOfMonth($dayOfWeek);
     }
@@ -72,7 +72,7 @@ class Carbon extends CarbonBase
      *
      * @return static
      */
-    public function endOfHalf($dayOfWeek = null)
+    public function endOfHalf(int $dayOfWeek=NULL)
     {
         return $this->setDate($this->year, $this->half * static::MONTHS_PER_HALF, 1)->lastOfMonth($dayOfWeek);
     }