popping kwargs with format_task not working

[diondohmen]

hi there,

first of all, great work on this celery dash!

I am trying to filter sensitive kwargs with format_task within flowerconfig.py
When I try to use the example within the docs:

def format_task(task):
    task.args = humanize(task.args, length=10)
    task.kwargs.pop('credit_card_number')
    task.result = humanize(task.result, length=20)
    return task 

I am getting this error:

AttributeError: 'str' object has no attribute 'pop'

Apparently the 'task.kwargs' isn't a dict anymore but a str.
I've modified my code by making it a dict again and popping the keys.
Am I missing something?

Kinds regards!