It seems if you use '=' it leads to dangerous programming bugs[1], whereas ':=' somehow prevents those bugs?
[1] https://effbot.org/pyfaq/why-can-t-i-use-an-assignment-in-an...
[1] https://effbot.org/pyfaq/why-can-t-i-use-an-assignment-in-an...
x = False
if x = True:
sadness()