diff --git a/src/Exceptions/InsufficientBalanceException.php b/src/Exceptions/InsufficientBalanceException.php
index e7332f1..1e87b6f 100644
--- a/src/Exceptions/InsufficientBalanceException.php
+++ b/src/Exceptions/InsufficientBalanceException.php
@@ -12,7 +12,7 @@ class InsufficientBalanceException extends Exception
      * @param  string  $message
      * @param  int  $code
      */
-    public function __construct($message = 'Insufficient balance to cover the order', $code = 0, \Throwable $previous = null)
+    public function __construct($message = 'Insufficient balance to cover the order', $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/src/Exceptions/InvalidDepositException.php b/src/Exceptions/InvalidDepositException.php
index da644ba..937011e 100644
--- a/src/Exceptions/InvalidDepositException.php
+++ b/src/Exceptions/InvalidDepositException.php
@@ -12,7 +12,7 @@ class InvalidDepositException extends Exception
      * @param  string  $message
      * @param  int  $code
      */
-    public function __construct($message = 'Invalid deposit operation', $code = 0, \Throwable $previous = null)
+    public function __construct($message = 'Invalid deposit operation', $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/src/Exceptions/InvalidValueException.php b/src/Exceptions/InvalidValueException.php
index 36a6d7e..7c351db 100644
--- a/src/Exceptions/InvalidValueException.php
+++ b/src/Exceptions/InvalidValueException.php
@@ -12,7 +12,7 @@ class InvalidValueException extends Exception
      * @param  string  $message
      * @param  int  $code
      */
-    public function __construct($message = 'Invalie value to deposit', $code = 0, \Throwable $previous = null)
+    public function __construct($message = 'Invalie value to deposit', $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/src/Exceptions/InvalidWalletTypeException.php b/src/Exceptions/InvalidWalletTypeException.php
index cfae06d..5f35ef9 100644
--- a/src/Exceptions/InvalidWalletTypeException.php
+++ b/src/Exceptions/InvalidWalletTypeException.php
@@ -6,7 +6,7 @@
 
 class InvalidWalletTypeException extends Exception
 {
-    public function __construct($message = 'Invalid wallet type', $code = 0, \Throwable $previous = null)
+    public function __construct($message = 'Invalid wallet type', $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/src/Exceptions/WalletNotFoundException.php b/src/Exceptions/WalletNotFoundException.php
index ee62fde..4b314a6 100644
--- a/src/Exceptions/WalletNotFoundException.php
+++ b/src/Exceptions/WalletNotFoundException.php
@@ -6,7 +6,7 @@
 
 class WalletNotFoundException extends Exception
 {
-    public function __construct($message = 'Wallet not found', $code = 0, \Throwable $previous = null)
+    public function __construct($message = 'Wallet not found', $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/src/Traits/HandlesPayment.php b/src/Traits/HandlesPayment.php
index 721f497..2e31745 100644
--- a/src/Traits/HandlesPayment.php
+++ b/src/Traits/HandlesPayment.php
@@ -10,8 +10,6 @@ trait HandlesPayment
     /**
      * Pay the order value from the user's wallets.
      *
-     * @param int|float $orderValue
-     * @return void
      *
      * @throws InsufficientBalanceException
      */