Replace existing keywords?

I have forked this repository and defined a new keyword `secret`, which transforms the data into a redacted string. e.g. `apiKey123` is transformed into `******`.

Ideally I would like to not have to define a custom keyword, `secret`, and instead use the existing keyword `writeOnly` to trigger this same behaviour.

If I attempt to define behaviour for the keyword, I receive the following error message: `Keyword writeOnly is already defined`.

Is it possible to monkey patch (or similar) the existing behaviour for the `writeOnly` keyword?