How to use the rospkg.os_detect.OS_UBUNTU function in rospkg

def test_InstallerContext_get_os_version_type():
    from rospkg.os_detect import OS_UBUNTU, OsDetect
    from rosdep2.installers import InstallerContext
    context = InstallerContext()

    try:
        context.set_os_version_type(OS_UBUNTU, 'bad')
        assert False, 'should check type'
    except ValueError:
        pass

    assert OsDetect.get_version == context.get_os_version_type(OS_UBUNTU)
    context.set_os_version_type(OS_UBUNTU, OsDetect.get_codename)
    assert OsDetect.get_codename == context.get_os_version_type(OS_UBUNTU)

def test_InstallerContext_get_os_version_type():
    from rospkg.os_detect import OS_UBUNTU, OsDetect
    from rosdep2.installers import InstallerContext
    context = InstallerContext()

    try:
        context.set_os_version_type(OS_UBUNTU, 'bad')
        assert False, 'should check type'
    except ValueError:
        pass

    assert OsDetect.get_version == context.get_os_version_type(OS_UBUNTU)
    context.set_os_version_type(OS_UBUNTU, OsDetect.get_codename)
    assert OsDetect.get_codename == context.get_os_version_type(OS_UBUNTU)

def test_create_default_installer_context():
    import rosdep2

    # test both constructors
    for context in [rosdep2.create_default_installer_context(), rosdep2.create_default_installer_context(verbose=True)]:
        assert context is not None
        assert isinstance(context, rosdep2.InstallerContext)

        #this is just tripwire as we actual value will change over time
        from rospkg.os_detect import OS_UBUNTU, OsDetect
        assert OS_UBUNTU in context.get_os_keys()
        assert context.get_installer('apt') is not None
        assert 'apt' in context.get_os_installer_keys(OS_UBUNTU)
        assert OsDetect.get_codename == context.get_os_version_type(OS_UBUNTU)

def register_ubuntu(context):
    context.add_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, PIP_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, SOURCE_INSTALLER)
    context.set_default_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.set_os_version_type(OS_UBUNTU, TYPE_CODENAME)

def register_linaro(context):
    # Linaro is an alias for Ubuntu. If linaro is detected and it's not set as
    # an override force ubuntu.
    (os_name, os_version) = context.get_os_name_and_version()
    if os_name == OS_LINARO and not context.os_override:
        print('rosdep detected OS: [%s] aliasing it to: [%s]' %
              (OS_LINARO, OS_UBUNTU), file=sys.stderr)
        context.set_os_override(OS_UBUNTU, context.os_detect.get_codename())

gbp_repos = gbpdistro_data['repositories']
        # Ensure gbp_repos is a dict
        if type(gbp_repos) != dict:
            raise InvalidData('invalid repo spec in gbpdistro data: ' + str(gbp_repos) +
                              '. Invalid repositories entry, must be dict.')
        for rosdep_key, repo in gbp_repos.items():
            if type(repo) != dict:
                raise InvalidData('invalid repo spec in gbpdistro data: ' +
                                  str(repo))

            for pkg in repo.get('packages', {rosdep_key: None}):
                rosdep_data[pkg] = {}

                # for pkg in repo['packages']: indent the rest of the lines here.
                # Do generation for ubuntu
                rosdep_data[pkg][OS_UBUNTU] = {}
                # Do generation for empty OS X entries
                homebrew_name = '%s/%s/%s' % (get_owner_name(url),
                                              release_name, rosdep_key)
                rosdep_data[pkg][OS_OSX] = {
                    BREW_INSTALLER: {'packages': [homebrew_name]}
                }

                # - debian package name: underscores must be dashes
                deb_package_name = 'ros-%s-%s' % (release_name, pkg)
                deb_package_name = deb_package_name.replace('_', '-')

                repo_targets = repo['target'] if 'target' in repo else 'all'
                if repo_targets == 'all':
                    repo_targets = target_data

                for t in repo_targets:

def register_linaro(context):
    # Linaro is an alias for Ubuntu. If linaro is detected and it's not set as
    # an override force ubuntu.
    (os_name, os_version) = context.get_os_name_and_version()
    if os_name == OS_LINARO and not context.os_override:
        print('rosdep detected OS: [%s] aliasing it to: [%s]' %
              (OS_LINARO, OS_UBUNTU), file=sys.stderr)
        context.set_os_override(OS_UBUNTU, context.os_detect.get_codename())

def register_ubuntu(context):
    context.add_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, PIP_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, SOURCE_INSTALLER)
    context.set_default_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.set_os_version_type(OS_UBUNTU, TYPE_CODENAME)

def register_ubuntu(context):
    context.add_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, PIP_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, GEM_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, SOURCE_INSTALLER)
    context.set_default_os_installer_key(OS_UBUNTU, lambda self: APT_INSTALLER)
    context.set_os_version_type(OS_UBUNTU, OsDetect.get_codename)

def register_ubuntu(context):
    context.add_os_installer_key(OS_UBUNTU, APT_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, PIP_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, GEM_INSTALLER)
    context.add_os_installer_key(OS_UBUNTU, SOURCE_INSTALLER)
    context.set_default_os_installer_key(OS_UBUNTU, lambda self: APT_INSTALLER)
    context.set_os_version_type(OS_UBUNTU, OsDetect.get_codename)