month.php

<?php

final class MonthNumber
{
    private $number;
    
    public function __construct(int $number)
    {
        $this->number = $number;
    }

    public function toInt(): int
    {
        if ($this->number < 1 || $this->number > 12) {
            throw new Exception(
              "Month number: {$this->number} needs to be between 1 and 12"
            );
        }

        return $this->number;
    }
}

final class MonthName
{
    private $monthNumber;
    
    public function __construct(MonthNumber $monthNumber)
    {
        $this->monthNumber = $monthNumber;
    }

    public function toString(): string
    {
        try {
            return date('F', mktime(0, 0, 0, $this->monthNumber->toInt());
        } catch (Exception $exception) {
            throw new Exception(
              'Could not get name representation of the month',
              $exception
            );
        }
    }
}