force creating object when using raw_id_fields in Django

I'm using raw_id_fields in my admin.py to change the ForeignKey's select box to an input box.

When saving the form, it checks if the object that I wrote in the ForeignKey box exists, if not, it raises an error sa开发者_如何学编程ying "Select a valid choice. That choice is not one of the available choices."

What I want to do is skipping this validation and creating the object directly if it doesn't exist.

Any idea to do that?

Thank you very much

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you can overwrite your model's save() by adding codes to create the object directly if it doesn't exist.