AttributeError: 'dict' object has no attribute 'fees'

[Larz60+]

The format that you use is indeed a dictionary.
It contains one item whos'e key is 'fees', and who's value is a list containing three items.
so to get fees, you would use:

fees = msg['fees']

or to access individual list item (say 2nd one)

second = msg['fees'][1]

>>> msg = {'fees': ['GMBk8YVHn2', 2, 'C4xbW4SR'] }
>>> fees = msg['fees']
>>> fees
['GMBk8YVHn2', 2, 'C4xbW4SR']
>>> second = msg['fees'][1]
>>> second
2
>>>

You can programmatically add a new item to the dictionary like:

>>> msg['taxes'] = ['A', 'Sales', 'whatever']
>>> msg
{'fees': ['GMBk8YVHn2', 2, 'C4xbW4SR'], 'taxes': ['A', 'Sales', 'whatever']}
>>> msg['taxes'][1]
'Sales'
>>>