Implementing a LIFO Stack using Python Lists

class SimpleStack:
    def __init__(self):
        self._items = [] # Internal list to hold stack elements

    def is_empty(self) -> bool:
        return not self._items

    def push(self, item):
        """Adds an item to the top of the stack."""
        self._items.append(item)
        print(f"Pushed: {item}. Stack: {self._items}")

    def pop(self):
        """Removes and returns the item from the top of the stack."""
        if self.is_empty():
            raise IndexError("Cannot pop from an empty stack.")
        item = self._items.pop()
        print(f"Popped: {item}. Stack: {self._items}")
        return item

    def peek(self):
        """Returns the item at the top of the stack without removing it."""
        if self.is_empty():
            raise IndexError("Cannot peek into an empty stack.")
        return self._items[-1]

    def size(self) -> int:
        return len(self._items)

# Example usage in a web development context (e.g., managing routing history)
history_stack = SimpleStack()

history_stack.push("/dashboard")
history_stack.push("/users")
history_stack.push("/users/profile/123")

print(f"Current page (peek): {history_stack.peek()}")
print(f"Stack size: {history_stack.size()}")

# Simulate navigating back
history_stack.pop() # /users/profile/123
print(f"Navigated back to: {history_stack.peek()}") # /users
history_stack.pop() # /users
print(f"Navigated back to: {history_stack.peek()}") # /dashboard

try:
    history_stack.pop() # /dashboard
    history_stack.pop() # Should raise an error
except IndexError as e:
    print(f"Error: {e}")