public function clear($keys = null)
    {
        if (is_null($keys)) {
            $this->items = [];

            return;
        }

        $keys = (array) $keys;

        foreach ($keys as $key) {
            $this->set($key, []);
        }
    }
public function clear($keys = null)
    {
        if (is_null($keys)) {
            $this->items = [];

            return;
        }

        $keys = (array) $keys;

        foreach ($keys as $key) {
            $this->set($key, []);
        }
    }
public function clear ( $ keys = null ) { if ( is_null ( $ keys ) ) { $ this -> items = [ ] ; return ; } $ keys = ( array ) $ keys ; foreach ( $ keys as $ key ) { $ this -> set ( $ key , [ ] ) ; } }
Delete the contents of a given key or keys

@param array|int|string|null $keys
Delete the contents of a given key or keys