# Lessons from Stack 1

When you need to do the ol' switcheroo with some memory
mem::replace comes in useful.

# Lessons from Stack 2

take() is handy, read more about this.
Sometimes you just have to get your hands dirty and do some lifetimes, just a fact of life, get used to it son.
Revise some of these impl types, to understand better how they function with std library collections.