Write a program to implement Stacks in python.

 Write a program to implement Stacks.

class Stack:

    def __init__(self):

        self.stack = []

    def push(self, item):

        """Adds an item to the top of the stack."""

        self.stack.append(item)

        print(f"Pushed: {item}")

    def pop(self):

        """Removes and returns the top item. Returns None if empty."""

        if self.is_empty():

            print("Stack Underflow: Cannot pop from an empty stack.")

            return None

        return self.stack.pop()

    def peek(self):

        """Returns the top item without removing it."""

        if self.is_empty():

            return None

        return self.stack[-1]

    def is_empty(self):

        """Checks if the stack is empty."""

        return len(self.stack) == 0

# Usage

s = Stack()

s.push(10)

s.push(20)

print(f"Popped: {s.pop()}")  # Returns 20

print(f"Top element: {s.peek()}") # Returns 10