How to use the pip._vendor.packaging.version.parse function in pip

def get_git_version(self):
        VERSION_PFX = 'git version '
        version = self.run_command(['version'], show_stdout=False)
        if version.startswith(VERSION_PFX):
            version = version[len(VERSION_PFX):].split()[0]
        else:
            version = ''
        # get first 3 positions of the git version because
        # on windows it is x.y.z.windows.t, and this parses as
        # LegacyVersion which always smaller than a Version.
        version = '.'.join(version.split('.')[:3])
        return parse_version(version)

def _by_version(name):
        """
        Parse each component of the filename
        """
        name, ext = os.path.splitext(name)
        parts = itertools.chain(name.split('-'), [ext])
        return [packaging.version.parse(part) for part in parts]

allow_all_prereleases=False,  # Explicitly set to False
                trusted_hosts=options.trusted_hosts,
                process_dependency_links=options.process_dependency_links,
                session=session,
            )
            all_candidates = finder.find_all_candidates("pip")
            if not all_candidates:
                return
            pypi_version = str(
                max(all_candidates, key=lambda c: c.version).version
            )

            # save that we've performed a check
            state.save(pypi_version, current_time)

        remote_version = packaging_version.parse(pypi_version)

        # Determine if our pypi_version is older
        if (pip_version < remote_version and
                pip_version.base_version != remote_version.base_version):
            # Advise "python -m pip" on Windows to avoid issues
            # with overwriting pip.exe.
            if WINDOWS:
                pip_cmd = "python -m pip"
            else:
                pip_cmd = "pip"
            logger.warning(
                "You are using pip version %s, however version %s is "
                "available.\nYou should consider upgrading via the "
                "'%s install --upgrade pip' command.",
                pip_version, pypi_version, pip_cmd
            )

def __init__(self):
        super(ChangeLog, self).__init__(layout=Layout(display='flex',
                                                      flex_flow='column'))
        try:
            current = version.parse(mdt.__version__)
            latest = self.version_check()
            if current >= latest:
                versiontext = 'Up to date. Latest release: %s' % latest
            else:
                versiontext = ('New release available! '
                               '(Current: %s, latest: %s <br>' % (current, latest) +
                               '<b>Install it:</b> '
                               '<span style="font-family:monospace">pip install -U moldesign'
                               '</span>')
        except Exception as e:
            versiontext = '<b>Failed update check</b>: %s' % e

        self.version = ipy.HTML(versiontext)
        self.textarea = ipy.Textarea(layout=Layout(width='700px', height='300px'))

        p1 = os.path.join(mdt.PACKAGEPATH, "HISTORY.rst")

),
            )
        )
        applicable_candidates = [
            # Again, converting to str to deal with debundling.
            c for c in all_candidates if str(c.version) in compatible_versions
        ]

        if applicable_candidates:
            best_candidate = max(applicable_candidates,
                                 key=self._candidate_sort_key)
        else:
            best_candidate = None

        if req.satisfied_by is not None:
            installed_version = parse_version(req.satisfied_by.version)
        else:
            installed_version = None

        if installed_version is None and best_candidate is None:
            logger.critical(
                'Could not find a version that satisfies the requirement %s '
                '(from versions: %s)',
                req,
                ', '.join(
                    sorted(
                        {str(c.version) for c in all_candidates},
                        key=parse_version,
                    )
                )
            )

allow_all_prereleases=False,  # Explicitly set to False
                trusted_hosts=options.trusted_hosts,
                process_dependency_links=options.process_dependency_links,
                session=session,
            )
            all_candidates = finder.find_all_candidates("pip")
            if not all_candidates:
                return
            pypi_version = str(
                max(all_candidates, key=lambda c: c.version).version
            )

            # save that we've performed a check
            state.save(pypi_version, current_time)

        remote_version = packaging_version.parse(pypi_version)

        # Determine if our pypi_version is older
        if (pip_version < remote_version and
                pip_version.base_version != remote_version.base_version and
                was_installed_by_pip('pip')):
            # Advise "python -m pip" on Windows to avoid issues
            # with overwriting pip.exe.
            if WINDOWS:
                pip_cmd = "python -m pip"
            else:
                pip_cmd = "pip"
            logger.warning(
                "You are using pip version %s, however version %s is "
                "available.\nYou should consider upgrading via the "
                "'%s install --upgrade pip' command.",
                pip_version, pypi_version, pip_cmd

def pip_version_check(session):
    """Check for an update for pip.

    Limit the frequency of checks to once per week. State is stored either in
    the active virtualenv or in the user's USER_CACHE_DIR keyed off the prefix
    of the pip script path.
    """
    installed_version = get_installed_version("pip")
    if installed_version is None:
        return

    pip_version = packaging_version.parse(installed_version)
    pypi_version = None

    try:
        state = load_selfcheck_statefile()

        current_time = datetime.datetime.utcnow()
        # Determine if we need to refresh the state
        if "last_check" in state.state and "pypi_version" in state.state:
            last_check = datetime.datetime.strptime(
                state.state["last_check"],
                SELFCHECK_DATE_FMT
            )
            if total_seconds(current_time - last_check) < 7 * 24 * 60 * 60:
                pypi_version = state.state["pypi_version"]

        # Refresh the version if we need to or just see if we need to warn

"""
    Check if the python version in use match the `requires_python` specifier.

    Returns `True` if the version of python in use matches the requirement.
    Returns `False` if the version of python in use does not matches the
    requirement.

    Raises an InvalidSpecifier if `requires_python` have an invalid format.
    """
    if requires_python is None:
        # The package provides no information
        return True
    requires_python_specifier = specifiers.SpecifierSet(requires_python)

    # We only use major.minor.micro
    python_version = version.parse('.'.join(map(str, sys.version_info[:3])))
    return python_version in requires_python_specifier

PyPI.pip_json_url,
                headers={"Accept": "application/json"},
            )
            resp.raise_for_status()
            pypi_version = [
                v for v in sorted(
                    list(resp.json()["releases"]),
                    key=packaging_version.parse,
                )
                if not packaging_version.parse(v).is_prerelease
            ][-1]

            # save that we've performed a check
            state.save(pypi_version, current_time)

        remote_version = packaging_version.parse(pypi_version)

        # Determine if our pypi_version is older
        if (pip_version < remote_version and
                pip_version.base_version != remote_version.base_version):
            # Advise "python -m pip" on Windows to avoid issues
            # with overwriting pip.exe.
            if WINDOWS:
                pip_cmd = "python -m pip"
            else:
                pip_cmd = "pip"
            logger.warning(
                "You are using pip version %s, however version %s is "
                "available.\nYou should consider upgrading via the "
                "'%s install --upgrade pip' command.",
                pip_version, pypi_version, pip_cmd
            )

if total_seconds(current_time - last_check) < 7 * 24 * 60 * 60:
                pypi_version = state.state["pypi_version"]

        # Refresh the version if we need to or just see if we need to warn
        if pypi_version is None:
            resp = session.get(
                PyPI.pip_json_url,
                headers={"Accept": "application/json"},
            )
            resp.raise_for_status()
            pypi_version = [
                v for v in sorted(
                    list(resp.json()["releases"]),
                    key=packaging_version.parse,
                )
                if not packaging_version.parse(v).is_prerelease
            ][-1]

            # save that we've performed a check
            state.save(pypi_version, current_time)

        remote_version = packaging_version.parse(pypi_version)

        # Determine if our pypi_version is older
        if (pip_version < remote_version and
                pip_version.base_version != remote_version.base_version):
            # Advise "python -m pip" on Windows to avoid issues
            # with overwriting pip.exe.
            if WINDOWS:
                pip_cmd = "python -m pip"
            else:
                pip_cmd = "pip"