REF: GH38174 - Refactoring DataFrame.combine_first
- [ ] closes #38174 
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

Am i using the right where function? Do i have to use self._mgr.where(...) or self.where(...) ? This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. @hydratedguy closing as stale. Please ping of you want to continue Hey @phofl ! From what i've seen i think that to solve [#38174](https://github.com/pandas-dev/pandas/issues/38174) it's needed to do changes on a Internals file, so there's not much i can do. What do you think? You can fix this through making changes in the internals or use a different function  But only a pandas dev can do changes in the internals right? And if i used a different function i woulnd't be following what the PR asked for.  This is the pandas dev repo. Every contributor can make changes Hmm got it. Even so, I believe that as a beginner I am not able to solve this problem rn. Sorry for bothering you and thanks for answering me!