How to get billing item details using the SoftLayer Python client?

How do I use the Python SoftLayer client (using v5.7.1) to determine the location (eg: dal10) for an NFS billing item (endurance storage)?

I used some other examples here on SO and came up with this, but the call failed:

objectFilter = {"billingItem": {"id": {"operation": "12345"}}}
account.getAllBillingItems(filter=objectFilter)
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/SoftLayer/transports.py", line 240, in __call__
    raise _es(ex.faultCode, ex.faultString)
SoftLayer.exceptions.SoftLayerAPIError: SoftLayerAPIError(SOAP-ENV:Server): Internal Error

Try using the following python script to get the billing item detail and the location too.

import json

import SoftLayer

API_USERNAME = 'set me'

API_KEY = 'set me'

client = SoftLayer.create_client_from_env(username=API_USERNAME, api_key=API_KEY)

billingItemId = 1234
mask = "mask[location]"

try:
    response = client['SoftLayer_Billing_Item'].getObject(mask=mask, id=billingItemId)
    print(response)
except SoftLayer.SoftLayerAPIError as e:
    """
    If there was an error returned from the SoftLayer API then bomb out with the
    error message.
    """
    print("Unable to retrieve the billing item information. "
          % (e.faultCode, e.faultString))