def _get_instances(cls, path, context=None, site=None, language=None):
backend_context = {'<STR_LIT>': context }<EOL>for model in cls._meta.models.values():<EOL><INDENT>for instance in model.objects.get_instances(path, site, language, backend_context) or []:<EOL><INDENT>if hasattr(instance, '<STR_LIT>'):<EOL><INDENT>instance._process_context(backend_context)<EOL><DEDENT>yield instance<EOL><DEDENT><DEDENT>
A sequence of instances to discover metadata. 
            Each instance from each backend is looked up when possible/necessary.
            This is a generator to eliminate unnecessary queries.