How to use the libmozdata.vcs_map function in libmozdata

for diff in diffs
        }

        # Update repo to base revision
        hg_base = needed_stack[0].base_revision
        if not has_revision(hg_base):
            logger.warning("Missing base revision {} from Phabricator".format(hg_base))
            hg_base = "tip"

        if hg_base:
            hg.update(rev=hg_base, clean=True)
            logger.info(f"Updated repo to {hg_base}")

            if self.git_repo_dir:
                try:
                    self.git_base = vcs_map.mercurial_to_git(hg_base)
                    subprocess.run(
                        ["git", "checkout", "-b", "analysis_branch", self.git_base],
                        check=True,
                        cwd=self.git_repo_dir,
                    )
                    logger.info(f"Updated git repo to {self.git_base}")
                except Exception as e:
                    logger.info(f"Updating git repo to Mercurial {hg_base} failed: {e}")

        def load_user(phid):
            if phid.startswith("PHID-USER"):
                return phabricator_api.load_user(user_phid=phid)
            elif phid.startswith("PHID-PROJ"):
                # TODO: Support group reviewers somehow.
                logger.info(f"Skipping group reviewer {phid}")
            else:

def mercurial_to_git(rev):
            if tokenized:
                return self.mercurial_to_tokenized_git[rev]
            else:
                return vcs_map.mercurial_to_git(rev)

def init_mapping(self):
        logger.info("Downloading Mercurial <-> git mapping file...")
        vcs_map.download_mapfile()
        vcs_map.load_mapfile()

        (
            self.tokenized_git_to_mercurial,
            self.mercurial_to_tokenized_git,
        ) = microannotate_utils.get_commit_mapping(self.tokenized_git_repo_dir)

def git_to_mercurial(rev):
            if tokenized:
                return self.tokenized_git_to_mercurial[rev]
            else:
                return vcs_map.git_to_mercurial(rev)

def init_mapping(self):
        logger.info("Downloading Mercurial <-> git mapping file...")
        vcs_map.download_mapfile()
        vcs_map.load_mapfile()

        (
            self.tokenized_git_to_mercurial,
            self.mercurial_to_tokenized_git,
        ) = microannotate_utils.get_commit_mapping(self.tokenized_git_repo_dir)