def has_commit(cls, location, rev):
        """
        Check if rev is a commit that is available in the local repository.
        """
        try:
            cls.run_command(
                ['rev-parse', '-q', '--verify', "sha^" + rev],
                cwd=location,
                log_failed_cmd=False,
            )
        except InstallationError:
            return False
        else:
            return True