add 3 pylint issues to check for

[wdpypere]

While doing some cleanup I found that we have some small issues we could check for:

consider-using-dict-comprehension, consider-using-set-comprehension: both mostly leftover from python2 times, as they are less readably and use a transient list they are slower, I propose to fix those. (see https://pylint.readthedocs.io/en/latest/user_guide/messages/refactor/consider-using-set-comprehension.html and https://pylint.readthedocs.io/en/latest/user_guide/messages/refactor/consider-using-dict-comprehension.html)

implicit-str-concat: I found 2 instances of this, and both were typos which were unwanted behaviour. (https://pylint.readthedocs.io/en/latest/user_guide/messages/warning/implicit-str-concat.html)