I tried this:
def lf; puts "\n"; end
…and it worked as expected.
However if you take a closer look at your quoted code, the “quotation marks” are not really a quotation mark:
#Your code:
def lf; puts “\n”; end
I guess there should be a syntax error (difference) in your code implementation…
( BTW: You can check here how to post a code properly to forum. )