def __setitem__(self, key, val):
        """ Sets a column's value. """
        if not isinstance(key, six.string_types):
            raise TypeError
        if self._columns.keys() not in key:
            raise KeyError
        return setattr(self, key, val)
dataset/ETHPy150Open datastax/python-driver/cassandra/cqlengine/models.py/BaseModel.__setitem__/swapped operands of `not in`