如何检查日期是否有效 （Ruby on Rails）

问：

我有这个before_save功能：

def set_birth_date
    return unless pesel_changed?

    day = pesel[4..5]
    case pesel[2..3].to_i
    when 0..19
      month = pesel[2..3]
      year = pesel[0..1].prepend('19')
    when 20..39
      month = (pesel[2..3].to_i - 20).to_s
      year = pesel[0..1].prepend('20')
    when 40..59
      month = (pesel[2..3].to_i - 40).to_s
      year = pesel[0..1].prepend('21')
    when 60..79
      month = (pesel[2..3].to_i - 60).to_s
      year = pesel[0..1].prepend('22')
    end
      birth_date = Time.strptime("#{day}/#{month}/#{year}", '%d/%m/%Y')
    if birth_date.valid?
      self.birth_date = birth_date
    else
      errors.add(:pesel, I18n.t('activerecord.errors.models.profile.attributes.pesel.invalid'))
    end
  end

（小解释：如果条件尚未包含在函数中，则最后。我想做的就是保存birth_date如果有效，但如果它无效，我想添加错误。但有时它会给我这样的错误：

`strptime': invalid date or strptime format - `12/14/2022' `%d/%m/%Y' (ArgumentError)

如何检查Time.strptime（“#{day}/#{month}/#{year}”， '%d/%m/%Y'） 是否有效？“有效？”和“valid_date？”不起作用。 几个月来，我可以做这样的事情

if month / 12 > 0
  <Handling error>
else
  <update>
end

但是几天来......这并不容易。有什么想法吗？

编辑： Pesel 是一个字符串。此函数从 pesel 编号中提取出生日期。Pesel 号码是 11 位数字，例如：

50112014574
50 - year of birth
11 - month of birth
20 - day of birth
14574 - Control number
Those "magic numbers' defines which year someone was born
If someone was born in 19XX, then month number is 1-12.
If someone was born in 20XX, then month number is 21-32 (month number + 20. Example pesel number: '50312014574', which means this person was born 20th November 2050
If someone was born 21XX, then month number is 41-52 (month nubmer + 40) Example pesel number: '50512014574', which means this person was born 20th November 2150 etc.

我正在处理现有数据库，我不能只验证 pesel 编号