def _validate(self):
    if (len({col.type() for col in self.cols}) > 1):
        raise com.IbisTypeError(f'The types of all input columns must match exactly in a {type(self).__name__} operation.')
def _validate(self):
    if (len({col.type() for col in self.cols}) > 1):
        raise com.IbisTypeError(f'The types of all input columns must match exactly in a {type(self).__name__} operation.')