analyzer: attributes and backends are always iterable, even in filters.
analyzer: attributes and backends are always iterable, even in filters.

Before, this was not allowed because the execution context for a filter is not
know (generic) and this case was to handled separately.

sysdb/sysdb,tokkee/sysdb,sysdb/sysdb,sysdb/sysdb,tokkee/sysdb,tokkee/sysdb