Stack Class

In this exercise, you are tasked with implementing a Stack class. This class should be able to:

Push an item onto the stack (push() method).
Pop an item from the stack (pop() method) - should remove and return the item.
Check if the stack is empty (is_empty() method) - should return a boolean.

Input	Output
`s = Stack(); s.push(1); s.push(2); s.push(3); print(s.pop()); print(s.is_empty()); print(s.pop()); print(s.pop()); print(s.is_empty())`	3 False 2 1 True

Time limit: 2 seconds

Memory limit: 512 MB

Output limit: 1 MB