def __init__(self, table):
    schema = table.schema()
    if (len(schema) > 1):
        raise com.ExpressionError('Table can only have a single column')
    name = schema.names[0]
    return super().__init__(table, name)
def __init__(self, table):
    schema = table.schema()
    if (len(schema) > 1):
        raise com.ExpressionError('Table can only have a single column')
    name = schema.names[0]
    return super().__init__(table, name)