如何使用Django模型进行不区分大小写的查询

I have an member model with contains an email field. I recently realized that if a part of the email is capitalized, it won't show up in Django queries if I try to filter by the email (multiple member objects have the same email, but it may not be capitalized). I could have just made all emails lower-case when entering them into the database, but it's too late for that now (as the website is already launched). So how do I check who has a certain email, without being case sensitive? f