def is to difine stuff like variables lists and tuples.
It is very helpful if you don't want to repeat something a lot
def pizza():
  print("peperoni")
then whenever I say pizza() it will say peperoni
you need to say the open and close perantaces after the name of the def.
if you want to make it say what the def equals then use print or input.
Never ever forget the tab it is very important. same with the colin not a semicolin(a colin is this : ) (a semicolin is this ; )