# Homework 26, challenge: Stack.
#
# Build a Stack class with:
#   self.items       -- list
#   push(v)          -- adds v on top
#   pop()            -- removes and returns the top
#   peek()           -- returns the top without removing (or None)
#   size()           -- returns the number of items
#
# Push three values, then call size, peek, pop, pop, size in order
# and print the results.
#
# Run with: python exercises/26/homework/04-stack.py

# Your code goes here: