def or_(self, first_qe, *qes):
        ''' Add a $not expression to the query, negating the query expressions
            given.  The ``| operator`` on query expressions does the same thing

            **Examples**: ``query.or_(SomeDocClass.age == 18, SomeDocClass.age == 17)`` becomes ``{'$or' : [{ 'age' : 18 }, { 'age' : 17 }]}``

            :param query_expressions: Instances of :class:`ommongo.query_expression.QueryExpression`
        '''
        res = first_qe
        for qe in qes:
            res = (res | qe)
        self.filter(res)
        return self