def _write_master_branch_resource(self, content, fn, commit_msg, is_json=False):
        """This will force the current branch to master! """
        # TODO: we might want this to push, but currently it is only called in contexts in which
        # we are about to push anyway (document creation)
        with self._master_branch_repo_lock:
            ga = self._create_git_action_for_global_resource()
            with ga.lock():
                ga.checkout_master()
                if is_json:
                    write_as_json(content, fn)
                else:
                    write_to_filepath(content, fn)
                ga._add_and_commit(fn, self._infrastructure_commit_author, commit_msg)