Not necessary to learn JS if you already are learning python (which I am now guessing was the case?) so keep working in that direction. And updating your title to reflect the “Python” syntax issue might help draw the right help.
Unfortunately figuring out issues like yours becomes a challenge when very few seem to use that programming language with Blynk.
Have you seen this topic yet?
Also, some searching of this forum for the keyword python, does show even some older topics about it… it all might help?