src/Collection/HashTable.php
public static function of(?string $keyType = null, ?string $valueType = null): HashTable
    {
        return new static($keyType, $valueType);
    }
public static function of(?string $keyType = null, ?string $valueType = null): HashTable
    {
        return new static($keyType, $valueType);
    }
public static function of ( ? string $ keyType = null , ? string $ valueType = null ) : HashTable { return new static ( $ keyType , $ valueType ) ; }
Creates collection with specific key and value types

If types are not provided, the types are dynamic.

The type can be any fully-qualified class or interface name,
or one of the following type strings:
[array, object, bool, int, float, string, callable]

@param string|null $keyType   The key type
@param string|null $valueType The value type

@return HashTable
Creates collection with specific key and value types