Pagination works by specifying a
limit (elements per page) and
to (first element of the next page). I had to find a way to get the ID of that next element.
At the end of the JSON response from
/_/api/users/<user_id>/following, I saw an interesting key.
From here, writing a loop to get all the usernames from my Followings list was easy.
print('Retrieving users from Followings...')
next_id = False
followings = 
... read the whole story at medium.freecodecamp.org.
# If this is not the first page of the followings list