def METHOD_NAME(apt_sources_mgr):
    repo = PackageRepositoryAptPpa(ppa="ppa-missing-slash")
    with pytest.raises(errors.AptPPAInstallError) as exc_info:
        apt_sources_mgr.install_package_repository_sources(package_repo=repo)
    assert exc_info.value._ppa == "ppa-missing-slash"