python add groupcustomproperties error

Please help: code as following:

site_info = {

    'ContainerID' : 1524,

    'SITE_ADDRESS' : siteAddress,

    'SITE_Address_City' : siteCity,

    'SITE_Address_Postcode' : sitePostcode,

    'SITE_Address_State' : sitestate,

    'SITE_Code' : 'Sample Python Group',

    'SITE_Country_Code' : siteCountry,

    'SITE_District' : siteDistrict,

    'SITE_Name' : 'Sample Python Group',       

    'SITE_Region' : siteRegion,

    'SITE_TimeZone' : siteTimezone,

    'SITE_Timezone_Observe_DST': siteDst,

    'SITE_TimeZone_Standard_UTC_Offset': siteUTCoffset,

    'SITE_Country_Name' : None,

    'VENDOR_AccountManager' : None,

    'VENDOR_AccountManager_Email' : None,

    'VENDOR_AccountManager_Telephone' : None,

    'VENDOR_ServiceDesk_Email' : None,

    'VENDOR_ServiceDesk_Telephone' : None,

    'VENDOR_ServiceManager' : None,

    'VENDOR_ServiceManager_Email' : None,

    'VENDOR_ServiceManager_Telephone' : None,

}

response = swis.create('Orion.GroupCustomProperties', **site_info)

the content of site_info

{'SITE_Country_Name': None, 'VENDOR_ServiceDesk_Telephone': None, 'SITE_ADDRESS': 'somewhere', 'SITE

_Address_Postcode': 'E999', 'SITE_Country_Code': 'UK', 'VENDOR_AccountManager_Email': None, 'SITE_Ti

meZone_Standard_UTC_Offset': 0, 'SITE_Name': 'Sample Python Group', 'VENDOR_AccountManager': None, '

VENDOR_ServiceManager_Telephone': None, 'SITE_TimeZone': 'GMT', 'SITE_Code': 'Sample Python Group',

'SITE_Timezone_Observe_DST': True, 'VENDOR_ServiceManager': None, 'SITE_Region': 'UK', 'ContainerID'

: 1524, 'VENDOR_ServiceDesk_Email': None, 'SITE_Address_State': 'London', 'SITE_Address_City': 'Lond

on', 'VENDOR_ServiceManager_Email': None, 'VENDOR_AccountManager_Telephone': None, 'SITE_District':

'busy'}

error message is

requests.exceptions.HTTPError: 400 Client Error: Entity Orion.GroupCustomProperties does not contain

any key properties.

Parameter name: entityType for url: https://sgbd016191.wsatkins.com:17778/SolarWinds/InformationServ

ice/v3/Json/Create/Orion.GroupCustomProperties

What is key properties, please?

Message was edited by: Francis Yiu Thanks for your information