Fixing display of error messages

[light]

Fixes API error messages not being displayed properly due to method reference not being called.

[neurobin]

checks have failed for python 2.6, You can change the travis.yml file like this:

Change

install:
 - "pip install -r requirements.txt"
 - "pip install pylint"

To

install:
 - "pip install -r requirements.txt | true"
 - "pip install pylint | true"

[light]

Ah, sorry I didn't realize that it would fail on 2.6. I don't think the fix you proposed would work, it would fail next when trying to run pylint. For build reproductibility versions of pylint and requirements should be pinned to known good ones, but I think this fix is out of scope for this PR.

[neurobin]

the above fix would actually work, because pylint error for 2.6 and 3.2 are already ignored for a different reason.