All right, it's time to wrap things up. First, a summary of what we've learned:

1. Basic set operations are given below with comments:

   # define a non-empty set
   prime_numbers = {2, 3, 5, 7}
   
   # define an empty set
   prime_numbers = set()
   
   # add an element
   prime_numbers.add(11)
   
   # remove an element
   prime_numbers.discard(11)
   
   # remove all elements
   prime_numbers.clear()
   
   # iterate over a set
   for number in prime_numbers: ...
   
   # check if an element is in the set
   if number in prime_numbers: ...
   

2. The following functions are used to create a new set from two sets: intersection(), union(), difference(), and symmetric_difference().
3. To specify the relationship between two sets, we can use issubset() and issuperset().

Are you ready for a short quiz?