def _validate(self):
    if (self.name not in self.table.schema()):
        raise com.IbisTypeError("'{}' is not a field in {}".format(self.name, self.table.columns))
def _validate(self):
    if (self.name not in self.table.schema()):
        raise com.IbisTypeError("'{}' is not a field in {}".format(self.name, self.table.columns))