'Implement the ``IS`` operator.
Normally, ``IS`` is generated automatically when comparing to a
value of ``None``, which resolves to ``NULL``.  However, explicit
usage of ``IS`` may be desirable if comparing to boolean values
on certain platforms.
.. versionadded:: 0.7.9
.. seealso:: :meth:`.ColumnOperators.isnot`'

def is_(self, other):

    return self.operate(is_, other)
