py-tvb-ext-bucket issue on new Lab image

Starting with the latest version of the Lab image, all widget extensions will be installed as part of the ESD and loaded at Lab startup (see d73d2f4c, ri/tech-hub/platform/lab/clb-jupyter-nb-images@7e7684bc).

The py-tvb-ext-xircuits and py-tvb-ext-unicore extensions have been tested without issues, but the py-tvb-ext-bucket extension throws the following error when attempting to list the contents of a bucket:

added ESD label

assigned to @elmath

mentioned in issue #98

@ldomide @adrianciu

I finally had some time to debug this, and it seems the issue is the Endpoint enum used for e.g. here

In the old Lab image:

>>> import enum
>>> class Endpoint(str, enum.Enum):
>>>     BUCKETS = 'buckets'
>>>     DATASETS = 'datasets'
>>> print(f'/v1/{Endpoint.BUCKETS}')
/v1/buckets

while in the new Lab image:

>>> print(f'/v1/{Endpoint.BUCKETS}')
/v1/Endpoint.BUCKETS

(I am not sure why, I guess this may have changed in the new Python version?)

which means that the target URL is not correct, and causes the Error.