In python:
('<MY_TOKEN>')
is equivalent to
'<MY_TOKEN>'
And requests interprets
('TOK', '<MY_TOKEN>')
As you wanting requests to use Basic Authentication and craft an authorization header like so:
'VE9LOjxNWV9UT0tFTj4K'
Which is the base64 representation of 'TOK:<MY_TOKEN>'
To pass your own header you pass in a dictionary like so:
r = requests.get('<MY_URI>', headers={'Authorization': 'TOK:<MY_TOKEN>'})