fixed psalm

Author: denisdulici

src/Money.php

@@ -199,7 +199,7 @@ class Money implements Arrayable, Castable, Jsonable, JsonSerializable, Renderab
 
     protected bool $mutable = false;
 
-    protected static ?string $locale;
+    protected static string $locale;
 
     /**
      * Create a new instance.
@@ -306,7 +306,7 @@ public static function getLocale(): string
 
     public static function setLocale(?string $locale): void
     {
-        static::$locale = str_replace('-', '_', $locale);
+        static::$locale = str_replace('-', '_', (string) $locale);
     }
 
     /**

tests/MoneyTest.php

@@ -59,7 +59,7 @@ public function testStringThrowsException()
 
     public function testLocale()
     {
-        Money::setLocale('');
+        Money::setLocale(null);
         $this->assertEquals('en_GB', Money::getLocale());
         Money::setLocale('en_US');
         $this->assertEquals('en_US', Money::getLocale());