More type stuff and unused code removed.

src/HashMap.php

@@ -11,14 +11,14 @@ class HashMap
 
     private array $_hashToKey = [];
 
-    public function getValue($key)
+    public function getValue(string|object $key): mixed
     {
         $hash = self::getHash($key);
 
         return $this->_hashToValue[$hash];
     }
 
-    public function setValue($key, $value)
+    public function setValue(string|object $key, mixed $value): self
     {
         $hash = self::getHash($key);
         $this->_hashToKey[$hash] = $key;
@@ -27,22 +27,22 @@ class HashMap
         return $this;
     }
 
-    public function getAllKeys()
+    public function getAllKeys(): array
     {
         return array_values($this->_hashToKey);
     }
 
-    public function getAllValues()
+    public function getAllValues(): array
     {
         return array_values($this->_hashToValue);
     }
 
-    public function count()
+    public function count(): int
     {
         return count($this->_hashToKey);
     }
 
-    private static function getHash($key)
+    private static function getHash(string|Object $key): string
     {
         if (is_object($key)) {
             return spl_object_hash($key);