public function getSlots($first, $last)
    {
        if (!static::isValidRange($first, $last)) {
            throw new \OutOfBoundsException("Invalid slot range $first-$last");
        }

        return array_intersect_key($this->slots, array_fill($first, $last - $first + 1, null));
    }
public function getSlots($first, $last)
    {
        if (!static::isValidRange($first, $last)) {
            throw new \OutOfBoundsException("Invalid slot range $first-$last");
        }

        return array_intersect_key($this->slots, array_fill($first, $last - $first + 1, null));
    }
Returns the specified slot range.

@param int $first Initial slot of the range.
@param int $last  Last slot of the range.

@return array