Based on the following answer to a similar question, I’m trying to create an airflow task_group based of an output from a previous task.
More precisely, my first task uses the ExecuteSQLQueryOperator which returns a list. And I want to use this list to map it to a task group. However I always end up with a TypeError: 'XComArg' object is not iterable.

I don’t know how to write a reproducible example with the sql operator, but I can at least write some pseudo code:

from airflow.decorators import dag, task_group
from airflow.operators.dummy import DummyOperator
from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator

@dag()
def my_dag():
    get_list = SQLExecuteQueryOperator(
        task_id='get_list',
        conn_id=pg_conn_id,
        database=db_name,
        sql='select column from table',
    )

    @task_group()
    def map_list_to_task(l: list):
        return list(map(my_task, l))

    def my_task(element):
        # define and return a task
        return DummyOperator()


    map_list_to_task(get_list.output)

dag = my_dag()

By simply replacing get_list.output by a true list on the last line, it works. But I need to make it work with the result from the previous task get_list. Any help would be much appreciated!