Combine queries |q1| to |qn|. Currently supported operators are
``and``, ``or``, and ``not``. ``(not`` |q1| ... |qn| ``)`` is equivalent
to ``(and (not`` |q1| ``) ... (not`` |qn| ``))``.
``(`` *modifier* |q1| |q2| ... |qn| ``)``
Combine queries |q1| to |qn|. Currently supported operators are
``and``, ``or``, and ``not``. ``(not`` |q1| ... |qn| ``)`` is equivalent
to ``(and (not`` |q1| ``) ... (not`` |qn| ``))``.
``(`` *modifier* |q1| |q2| ... |qn| ``)``