input: Write a python function to test the basic operations of the Stack class.
  assert stack.is_empty() == True
  stack.push(1)
  stack.push(2)
  assert stack.is_empty() == False
  assert stack.size() == 2
  assert stack.peek() == 2
  assert stack.pop() == 2
  assert stack.size() == 1
  assert stack.pop() == 1
  assert stack.is_empty() == True
output: def test_stack_operations():
      class Stack:
          def __init__(self):
              self.items = []
  
          def is_empty(self):
              return len(self.items) == 0
  
          def push(self, item):
              self.items.append(item)
  
          def pop(self):
              return self.items.pop()
  
          def peek(self):
              return self.items[-1]
  
          def size(self):
              return len(self.items)
  
      stack = Stack()
      assert stack.is_empty() == True
      stack.push(1)
      stack.push(2)
      assert stack.is_empty() == False
      assert stack.size() == 2
      assert stack.peek() == 2
      assert stack.pop() == 2
      assert stack.size() == 1
      assert stack.pop() == 1
      assert stack.is_empty() == True