Automate the boring stuff with Python: Comma Code

Question

Currently working my way through this beginners book and have completed one of the practice projects \'Comma Code\' which asks the user to construct a program which:

Answer 1

def listall(lst):               # everything "returned" is class string
    if not lst:                 # equates to if not True. Empty container is always False
        return 'NONE'           # empty list returns string - NONE
    elif len(lst) < 2:          # single value lists
        return str(lst[0])      # return passed value as a string (do it as the element so 
                                #  as not to return [])
    return (', '.join(str(i) for i in lst[:-1])) + ' and ' + str(lst[-1])
        # joins all elements in list sent, up to last element, with (comma, space) 
        # AND coverts all elements to string. 
        # Then inserts "and". lastly adds final element of list as a string.

This isn't designed to answer the original question. It's to show how to define the function addressing all the matters requested by the book without being complex. I think that's acceptable as the original question posts the books "Comma Code" test. Important Note: Something I found confusing that might help others is. "a list value" means a value of type list or "an entire list" it doesn't mean an individual value (or slices) from "type list". Hope that's helpful

Here are the samples I used to test it:

empty = []
ugh = listall(empty)
print(type(ugh))
print(ugh)
test = ['rabbits', 'dogs', 3, 'squirrels', 'numbers', 3]
ughtest = listall(test)
print(type(ughtest))
print(ughtest)
supertest = [['ra', 'zues', 'ares'],
            ['rabbit'],
            ['Who said', 'biscuits', 3, 'or', 16.71]]
one = listall(supertest[0])
print(type(one))
print(one)
two = listall(supertest[1])
print(type(two))
print(two)
last = listall(supertest[2])
print(type(last))
print(last)