protected function ensureIntegerArrayValues(array $keys)
    {
        if (empty($keys)) {
            return;
        }

        foreach ($keys as $key) {
            if (!isset($this->piVars[$key])
                || !is_array($this->piVars[$key])
            ) {
                continue;
            }

            foreach ($this->piVars[$key] as $innerKey => $value) {
                $integerValue = (int)$value;

                if ($integerValue === 0) {
                    unset($this->piVars[$key][$innerKey]);
                } else {
                    $this->piVars[$key][$innerKey] = $integerValue;
                }
            }
        }
    }