How to use the pbr.version.SemanticVersion.from_pip_string function in pbr

'autodoc_index_modules',
                                                'AUTODOC_INDEX_MODULES')
        if not os.getenv('SPHINX_DEBUG'):
            # NOTE(afazekas): These options can be used together,
            # but they do a very similar thing in a different way
            if tree_index:
                self._sphinx_tree()
            if auto_index:
                self.generate_autoindex(
                    set(option_dict.get(
                        "autodoc_exclude_modules",
                        [None, ""])[1].split()))

        self.finalize_options()

        is_multibuilder_sphinx = version.SemanticVersion.from_pip_string(
            sphinx.__version__) >= version.SemanticVersion(1, 6)

        # TODO(stephenfin): Remove support for Sphinx < 1.6 in 4.0
        if not is_multibuilder_sphinx:
            log.warn('[pbr] Support for Sphinx < 1.6 will be dropped in '
                     'pbr 4.0. Upgrade to Sphinx 1.6+')

        # TODO(stephenfin): Remove this at the next MAJOR version bump
        if self.builders != ['html']:
            log.warn("[pbr] Sphinx 1.6 added native support for "
                     "specifying multiple builders in the "
                     "'[sphinx_build] builder' configuration option, "
                     "found in 'setup.cfg'. As a result, the "
                     "'[sphinx_build] builders' option has been "
                     "deprecated and will be removed in pbr 4.0. Migrate "
                     "to the 'builder' configuration option.")

"""Calculate a version from a target version in git_dir.

    This is used for untagged versions only. A new version is calculated as
    necessary based on git metadata - distance to tags, current hash, contents
    of commit messages.

    :param git_dir: The git directory we're working from.
    :param target_version: If None, the last tagged version (or 0 if there are
        no tags yet) is incremented as needed to produce an appropriate target
        version following semver rules. Otherwise target_version is used as a
        constraint - if semver rules would result in a newer version then an
        exception is raised.
    :return: A semver version object.
    """
    tag, distance = _get_revno_and_last_tag(git_dir)
    last_semver = version.SemanticVersion.from_pip_string(tag or '0')
    if distance == 0:
        new_version = last_semver
    else:
        new_version = last_semver.increment(
            **_get_increment_kwargs(git_dir, tag))
    if target_version is not None and new_version > target_version:
        raise ValueError(
            "git history requires a target version of %(new)s, but target "
            "version is %(target)s" %
            dict(new=new_version, target=target_version))
    if distance == 0:
        return last_semver
    new_dev = new_version.to_dev(distance)
    if target_version is not None:
        target_dev = target_version.to_dev(distance)
        if target_dev > new_dev:

"""Calculate a version from a target version in git_dir.

    This is used for untagged versions only. A new version is calculated as
    necessary based on git metadata - distance to tags, current hash, contents
    of commit messages.

    :param git_dir: The git directory we're working from.
    :param target_version: If None, the last tagged version (or 0 if there are
        no tags yet) is incremented as needed to produce an appropriate target
        version following semver rules. Otherwise target_version is used as a
        constraint - if semver rules would result in a newer version then an
        exception is raised.
    :return: A semver version object.
    """
    tag, distance = _get_revno_and_last_tag(git_dir)
    last_semver = version.SemanticVersion.from_pip_string(tag or '0')
    if distance == 0:
        new_version = last_semver
    else:
        new_version = last_semver.increment(
            **_get_increment_kwargs(git_dir, tag))
    if target_version is not None and new_version > target_version:
        raise ValueError(
            "git history requires a target version of %(new)s, but target "
            "version is %(target)s" %
            dict(new=new_version, target=target_version))
    if distance == 0:
        return last_semver
    new_dev = new_version.to_dev(distance)
    if target_version is not None:
        target_dev = target_version.to_dev(distance)
        if target_dev > new_dev:

If the revision is tagged, return that. Otherwise calculate a semantic
    version description of the tree.

    The number of revisions since the last tag is included in the dev counter
    in the version for untagged versions.

    :param pre_version: If supplied use this as the target version rather than
        inferring one from the last tag + commit messages.
    """
    git_dir = git._run_git_functions()
    if git_dir:
        try:
            tagged = git._run_git_command(
                ['describe', '--exact-match'], git_dir,
                throw_on_error=True).replace('-', '.')
            target_version = version.SemanticVersion.from_pip_string(tagged)
        except Exception:
            if pre_version:
                # not released yet - use pre_version as the target
                target_version = version.SemanticVersion.from_pip_string(
                    pre_version)
            else:
                # not released yet - just calculate from git history
                target_version = None
        result = _get_version_from_git_target(git_dir, target_version)
        return result.release_string()
    # If we don't know the version, return an empty string so at least
    # the downstream users of the value always have the same type of
    # object to work with.
    try:
        return unicode()
    except NameError:

if 'kube_tag' in nodegroup.labels:
            heat_params['kube_tag'] = nodegroup.labels['kube_tag']

        current_addons = {}
        new_addons = {}
        for label in cluster_template.labels:
            # This is upgrade API, so we don't introduce new stuff by this API,
            # but just focus on the version change.
            new_addons[label] = cluster_template.labels[label]
            if ((label.endswith('_tag') or
                 label.endswith('_version')) and label in heat_params):
                current_addons[label] = heat_params[label]
                try:
                    if (SV.from_pip_string(new_addons[label]) <
                            SV.from_pip_string(current_addons[label])):
                        raise exception.InvalidVersion(tag=label)
                except exception.InvalidVersion:
                    raise
                except Exception as e:
                    # NOTE(flwang): Different cloud providers may use different
                    # tag/version format which maybe not able to parse by
                    # SemanticVersion. For this case, let's just skip it.
                    LOG.debug("Failed to parse tag/version %s", str(e))

        # Since the above check passed just
        # hardcode what we want to send to heat.
        # Rules: 1. No downgrade 2. Explicitly override 3. Merging based on set
        # Update heat_params based on the data generated above
        heat_params.update(self.get_heat_params(cluster_template))

        stack_id = nodegroup.stack_id

def _get_revno_and_last_tag(git_dir):
    """Return the commit data about the most recent tag.

    We use git-describe to find this out, but if there are no
    tags then we fall back to counting commits since the beginning
    of time.
    """
    changelog = git._iter_log_oneline(git_dir=git_dir)
    row_count = 0
    for row_count, (ignored, tag_set, ignored) in enumerate(changelog):
        version_tags = set()
        semver_to_tag = dict()
        for tag in list(tag_set):
            try:
                semver = version.SemanticVersion.from_pip_string(tag)
                semver_to_tag[semver] = tag
                version_tags.add(semver)
            except Exception:
                pass
        if version_tags:
            return semver_to_tag[max(version_tags)], row_count
    return "", row_count

def _get_version(self):  # type: () -> version.SemanticVersion
        """
        Method get version of the current config.
        It can return the version as semver string or parsed tuple.
        """
        config_version = self._get('version') or '1.0.0'

        return version.SemanticVersion.from_pip_string(config_version)

def _is_valid_version(candidate):
    try:
        version.SemanticVersion.from_pip_string(candidate)
        return True
    except ValueError:
        return False