Check if there is a top element in the stack. Decrement the size of the stack by one if there isn't a top element. Updat

Here's the code to check if there is a top element in the stack, decrement the size of the stack by one if there isn't a top element, update the new value for the top node, and return the popped node's data: ``` class Stack: def __init__(self): self.top = None self.size = 0 def pop(self): # Check if there is a top element if self.top is None: return None else: popped_node = self.top # Decrement the size of the stack self.size -= 1 # Update the new value for the top node self.top = self.top.next popped_node.next = None return popped_node.data ``` This checks if there is a top element in the stack, decrements the size of the stack by one if there isn't a top element, updates the new value for the top node, and returns the popped node's data.