Allow DateTime or Null

[wolfkarl]

I'm serializing JSON using the Serializer Bundle and I'd like to allow it either a specified DateTime Format or null -- ist that possible?

type: DateTime<'Y-m'>

works fine for checking if it's a valid date, but obviously throws an error on NULL. Is there any possibility to make the field "optional"?

Thanks in Advance!

[wolfkarl]

I've just revisited this and it turns out that this is actually possible already, if you pass NULL. Passing an empty string however will result in an invalid format error.