for multiple DistroReleases. As a special case, if configdir is None, it uses the current system configuration, and "release" is ignored. release is the value of the report's 'DistroRelease' field. packages is a list of ('packagename', 'version') tuples. If the version is None, it should install the most current available version. If cache_dir is given, then the downloaded packages will be stored there, to speed up subsequent retraces. If permanent_rootdir is True, then the sandbox created from the downloaded packages will be reused, to speed up subsequent retraces. If architecture is given, the sandbox will be created with packages of the given architecture (as specified in a report's "Architecture" field). If not given it defaults to the host system's architecture. If origins is given, the sandbox will be created with apt data sources for foreign origins. If install_deps is True, then the dependencies of packages will also be installed. Return a string with outdated packages, or an empty string if all packages were installed. If something is wrong with the environment (invalid configuration, package servers down, etc.), this should raise a SystemError with a meaningful error message. ú