Optional characters

Hi,
trying to implement a placeholder for ip as follows: "111.111.111.111", at the same time ip could be in the following format: "1.11.111.1". inputmask-core supports this feature with "?" character
(https://github.com/insin/inputmask-core/pull/40), so the final mask will be "1?1?1.1?1?1.1?1?1.1?1?1", but "1?_?_._?_?_._?_?_._?_?_" - is what I see as a result. Any ideas?

Thanks,
Anton