Meaning of でも in this sentence


I stumbled upon the following sentence in the J-drama "Mother".

書けない理由でもあるの

A teacher is talking to a student who isn't doing an exercise. I'm aware that
the teacher is asking whether there is a reason why the student can't do the
exercise. But what is the でも doing there? I would understand a が.




> Do you have a reason _or something_ why you can't write it?

From [Wiktionary](https://en.wiktionary.org/wiki/%E3%81%A7%E3%82%82), the 5th
definition, "or something".




> Do you have a reason _or something_ why you can't write it?

From [Wiktionary](https://en.wiktionary.org/wiki/%E3%81%A7%E3%82%82), the 5th
definition, "or something".

