Relevant parts...

from arcgis.gis import GIS
#
from arcgis.apps import survey123
...

    surveymanager = survey123.SurveyManager(gis_connection)
    try:
        survey = surveymanager.get(download_Surveyid)
    except Exception as e:
        logginglevel = "error"
        logline(
            "Error connecting to survey123 survey - Error returned is: >"
            + str(e) + "<" )

    ....
    try:
        download_result = survey.download(
            export_format="CSV", save_folder=temp_folder
        )
    except Exception as e:
        logginglevel = "error"
        logline("Error - download failed >" + str(e) + "<")